Dr. Harris' Original Women's Libido by GHC Associates

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Allergic rhinitis (hay fever). Although there has been interest in using oral black pepper for allergic rhinitis, there is insufficient reliable information about the clinical effects of black pepper for this purpose.
• Asthma. Although there has been interest in using oral black pepper for asthma, there is insufficient reliable information about the clinical effects of black pepper for this purpose.
• Athletic performance. Oral black pepper has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One small clinical trial in untrained males shows that taking a supplement containing black pepper extract 10 mg, caffeine 400 mg, capsicum extract 66.7 mg, and niacin 40 mg as a single dose prior to exercise does not improve strength, time to exhaustion, or maximal oxygen consumption when compared with placebo (37873).
• Depression. Although there has been interest in using oral black pepper for depression, there is insufficient reliable information about the clinical effects of black pepper for this purpose.
• Diarrhea. Although there has been interest in using oral black pepper for diarrhea, there is insufficient reliable information about the clinical effects of black pepper for this purpose.
• Dysmenorrhea. Although there has been interest in using oral black pepper for dysmenorrhea, there is insufficient reliable information about the clinical effects of black pepper for this purpose.
• Dyspepsia. Although there has been interest in using oral black pepper for dyspepsia, there is insufficient reliable information about the clinical effects of black pepper for this purpose.
• Fall prevention. It is unclear if inhaling black pepper oil as aromatherapy is beneficial for fall prevention in older adults. Details: One small clinical study in older adults shows that applying black pepper oil near the right side of the nose as an olfactory stimulant improves stability while the eyes are closed during a one-minute trial when compared with the application of water. The improvement with black pepper oil is comparable to the improvement seen with the application of lavender oil (29160). It is unclear if any benefit persists after inhalation of black pepper oil.
• Fatigue. It is unclear if oral black pepper is beneficial in patients with fatigue. Details: One small clinical trial in adults with below-average energy levels shows that taking black pepper 2 grams as a single dose does not improve sustained attention, motivation to perform cognitive tasks, or feelings of mental energy and mental fatigue when compared with placebo (91731).
• Flatulence. Although there has been interest in using oral black pepper for flatulence, there is insufficient reliable information about the clinical effects of black pepper for this purpose.
• Headache. Although there has been interest in using oral black pepper for headache, there is insufficient reliable information about the clinical effects of black pepper for this purpose.
• Insect bite. Topical black pepper has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One small clinical trial shows that applying a specific product (Trikatu) containing black pepper, long pepper, and ginger, as well as camphor, eucalyptus oil, and menthol, directly to mosquito bites does not reduce papule size, erythema, edema, or pruritis when compared with a control compound containing the same base ingredients but without the pepper and ginger components (89893).
• Obesity. Although there has been interest in using oral black pepper for obesity, there is insufficient reliable information about the clinical effects of black pepper for this purpose.
• Pain (chronic). Although there has been interest in using topical black pepper for chronic pain related to various etiologies, including osteoarthritis, postherpetic neuralgia, and peripheral neuropathy, there is insufficient reliable information about the clinical effects of black pepper for these conditions.
• Rhinosinusitis. Although there has been interest in using oral black pepper for rhinosinusitis, there is insufficient reliable information about the clinical effects of black pepper for this purpose.
• Sexual desire. Although there has been interest in using oral black pepper for increasing sexual desire, there is insufficient reliable information about the clinical effects of black pepper for this purpose.
• Smoking cessation. It is unclear if inhaling black pepper essential oil as aromatherapy is effective for smoking cessation. Details: One small clinical trial in adult male smokers who were deprived from smoking overnight shows that inhaling a vapor from the essential oil of black pepper, as needed over a 3-hour period, reduces cigarette cravings, negative feelings, and anxiety when compared with a placebo vapor (29159). Another small clinical study in patients addicted to dipping, chewing, or smoking tobacco shows that placing a drop of black pepper essential oil on tissue paper and inhaling for 2 minutes at least three times a day for 3 days reduces nicotine cravings when compared to baseline (90502).
• Swallowing dysfunction. It is unclear if inhaling black pepper oil as aromatherapy is beneficial in patients with swallowing dysfunction. Details: One small clinical study in post-stroke residents of nursing homes shows that one minute of olfactory stimulation with black pepper oil before each meal for 30 days decreases swallowing reflex latency by 11 seconds and increases the number of swallowing movements by 3.3 when compared to baseline (29161). A small clinical trial in children with neurological disorders who were on long-term enteral nutrition shows that applying black pepper oil to the nostrils or nasal cavity for one minute improves the amount of oral intake and swallowing movement in 63% of patients. Although oral intake increased, the need for enteral nutrition was not eliminated (29162).
• Vitiligo. It is unclear if topical piperine oil, a constituent of black pepper, is beneficial in patients with vitiligo. Details: A small clinical study in patients with vitiligo shows that applying piperine oil 1% daily in addition to receiving narrowband ultraviolet B (NB-UVB) light therapy every other day for 3 months improves repigmentation more rapidly when compared with using NB-UVB alone (103820). More evidence is needed to rate black pepper for these uses.

(Read more about BLACK PEPPER)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Asthma. Although there has been interest in using oral damiana for asthma, there is insufficient reliable information about the clinical effects of damiana for this purpose.
• Cognitive function. Although there has been interest in using oral damiana for cognitive function, there is insufficient reliable information about the clinical effects of damiana for this purpose.
• Constipation. Although there has been interest in using oral damiana for constipation, there is insufficient reliable information about the clinical effects of damiana for this purpose.
• Depression. Although there has been interest in using oral damiana for depression, there is insufficient reliable information about the clinical effects of damiana for this purpose.
• Diabetes. Although there has been interest in using oral damiana for diabetes, there is insufficient reliable information about the clinical effects of damiana for this purpose.
• Dyspepsia. Although there has been interest in using oral damiana for dyspepsia, there is insufficient reliable information about the clinical effects of damiana for this purpose.
• Erectile dysfunction (ED). Oral damiana has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A moderate-sized, open-label clinical study in adults with mild-to-moderate ED shows that taking a specific combination supplement (Icarifil, Anvest Health S.p.A) containing damiana 100 mg, panax ginseng, L-carnitine, L-citrulline, tribulus, and other ingredients daily for 3 months improves patient-reported erectile function when compared to baseline. Additionally, taking the supplement with tadalafil improves some, but not all, patient-reported assessments of erectile function when compared with taking tadalafil alone (114989). It is unclear if this effect is due to damiana, other ingredients, or the combination. Additionally, the interpretation of these results is limited by poor methodology, including the use of per-protocol analysis and lack of a placebo group.
• Headache. Although there has been interest in using oral damiana for headache, there is insufficient reliable information about the clinical effects of damiana for this purpose.
• Menopausal symptoms. Although there has been interest in using oral damiana for menopausal symptoms, there is insufficient reliable information about the clinical effects of damiana for this purpose.
• Obesity. Oral damiana has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in overweight adults shows that taking a combination product containing damiana 36 mg, guarana 95 mg, and yerba mate 112 mg, orally three times daily for 45 days increases weight loss when compared with placebo (11866). It is unclear if this effect is due to damiana, other ingredients, or the combination.
• Nocturnal enuresis. Although there has been interest in using oral damiana for nocturnal enuresis, there is insufficient reliable information about the clinical effects of damiana for this purpose.
• Sexual dysfunction. Oral damiana has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that taking a specific combination product containing damiana, L-arginine, Panax ginseng, ginkgo, vitamins, and minerals (ArginMax for Women, Daily Wellness Co.) improves sexual satisfaction and desire, increases orgasm frequency, and reduces vaginal dryness when compared with placebo in females interested in improving their sexual function (46933). It is unclear if this effect is due to damiana, other ingredients, or the combination. More evidence is needed to rate damiana for these uses.

(Read more about DAMIANA)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Atopic dermatitis (eczema). Although there is interest in using oral dong quai for atopic dermatitis, there is insufficient reliable information about the clinical effects of dong quai for this condition.
• Chronic kidney disease (CKD). There is limited evidence on the use of dong quai in patients with CKD. Details: A large propensity score-matched observational study over 15 years in Taiwanese adults with CKD suggests that taking dong quai is associated with a 5.1% risk of end-stage renal disease (ESRD) and 38% risk of overall mortality when compared with 7% and 56%, respectively, in controls. Higher cumulative doses (i.e., 15 grams or more) and longer duration of exposure (i.e., > 60 days) are also associated with fewer ESRD events (112362). However, the interpretation of these findings is limited by the lack of exact dosage information and retrospective study design.
• Coronary heart disease (CHD). Intravenous dong quai has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients with CHD shows that injecting 20 mL of an intravenous solution containing dong quai, ginseng, and astragalus (Yi-qi Huo-xue Injection) daily for 2 weeks reduces the frequency and severity of angina episodes when compared with placebo. It also seems to increase exercise tolerance and improve left ventricular function when compared with placebo (33046). It is unclear if these benefits are due to dong quai, other ingredients, or the combination.
• Dysmenorrhea. Although there is interest in using oral dong quai for dysmenorrhea, there is insufficient reliable information about the clinical effects of dong quai for this condition.
• Hypertension. Although there is interest in using oral dong quai for hypertension, there is insufficient reliable information about the clinical effects of dong quai for this purpose.
• Idiopathic interstitial pneumonia. Oral dong quai has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A meta-analysis of 17 studies conducted in China in patients with idiopathic interstitial pneumonia concludes that adding traditional Chinese medicine combinations containing dong quai root and astragalus root to treatment with conventional medicines improves pulmonary function index, six-minute walking distance, and the Borg scale of perceived exertion when compared with conventional treatment alone (103618). The included studies are of low quality, include a range of treatment durations from 1-12 months, and vary in the conventional medicines and Chinese herb combinations used. The doses of dong quai used were not stated.
• Infertility. Although there is interest in using oral dong quai for infertility, there is insufficient reliable information about the clinical effects of dong quai for this condition.
• Iron deficiency anemia. Although there is interest in using oral dong quai for iron deficiency anemia, there is insufficient reliable information about the clinical effects of dong quai for this condition.
• Menopausal symptoms. There is inconsistent and contradictory evidence about the effect of dong quai on menopausal symptoms. Benefits have only been seen when it is used in combination with other ingredients; its effect when used alone is unclear. Details: Some clinical research shows that taking dong quai, 1.5 grams three times daily for 24 weeks, does not affect menopausal symptoms (738). Other clinical research shows that dong quai improves menopausal symptoms when used in combination with other constituents. In one clinical trial, taking five chewable tablets of a specific combination of dong quai and chamomile (Climex) daily for 12 weeks reduced the frequency and severity of hot flushes when compared with placebo (48445). In another trial, taking a combination providing dong quai 75 mg, along with American ginseng, black cohosh, milk thistle, red clover, and vitex agnus-castus (Phyto-Female Complex) twice daily for 3 months reduces menopausal symptoms, including the number and intensity of hot flushes, the number of night sweats, and sleep quality (19552). Taking another combination product containing dong quai, burdock root, licorice root, motherwort, and Mexican wild yam root, 500 mg three times daily for 3 months, also reduces menopausal symptoms when compared with placebo (48522). It is unclear if the beneficial effects in these studies were due to dong quai, other ingredients, or a combination of ingredients.
• Migraine headache. Oral dong quai has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients with menstrual migraine shows that taking a combination of soy isoflavones 60 mg, dong quai 100 mg, and black cohosh 50 mg daily for 24 weeks reduces the frequency of attacks when compared with placebo (35797). It is unclear if this effect is due to dong quai, other ingredients, or the combination.
• Osteoporosis. Although there is interest in using oral dong quai for osteoporosis, there is insufficient reliable information about the clinical effects of dong quai for this condition.
• Peptic ulcers. Although there is interest in using oral dong quai for peptic ulcers, there is insufficient reliable information about the clinical effects of dong quai for this condition.
• Premature ejaculation. Topical dong quai has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: In one preliminary clinical trial in patients with premature ejaculation, a multi-ingredient cream preparation (SS Cream) containing dong quai, Panax ginseng root, Cistanches deserticola, Zanthoxyl species, Torlidis seed, clove flower, Asiasari root, cinnamon bark, and toad venom was applied to the glans penis 1 hour prior to intercourse and washed off immediately before intercourse. Patients using the cream had significantly improved ejaculatory latency when compared with placebo cream (2537). It is unclear if this effect is due to dong quai, other ingredients, or the combination.
• Premenstrual syndrome (PMS). Although there is interest in using oral dong quai for PMS, there is insufficient reliable information about the clinical effects of dong quai for this condition.
• Psoriasis. Although there is interest in using oral dong quai for psoriasis, there is insufficient reliable information about the clinical effects of dong quai for this condition.
• Pulmonary hypertension. Preliminary clinical research shows that intravenous dong quai may be effective in patients with pulmonary hypertension. Details: Some preliminary clinical research in patients with chronic obstructive pulmonary disease (COPD) and pulmonary hypertension shows that intravenous administration of 250 mL of a solution containing dong quai 25%, once daily for 5-10 days, reduces pulmonary arterial pressure and pulmonary vascular resistance when compared to baseline (48438,48442,48443). The validity of these findings is limited by the lack of comparator groups.
• Rheumatoid arthritis (RA). Although there is interest in using oral dong quai for RA, there is insufficient reliable information about the clinical effects of dong quai for this condition.
• Stroke. Preliminary evidence does not support the use of intravenous dong quai for acute ischemic stroke. Details: Preliminary clinical research in patients with acute ischemic stroke shows that administering 200 mL of a solution containing dong quai 25% intravenously daily for 20 days does not improve neurological symptoms when compared with dextran-40 (48483). More evidence is needed to rate dong quai for these uses.

(Read more about DONG QUAI)

POSSIBLY EFFECTIVE

• Anxiety. Oral kava seems to improve anxiety when taken for at least 5 weeks. Details: Most clinical research shows that kava extracts 150-400 mg, standardized to 70% kavalactones, daily are superior to placebo for relieving symptoms of non-psychotic anxiety (2094,2095,11372,18315,18316,18317,18320,98980), and are possibly comparable to buspirone 10 mg or low-dose benzodiazepines such as oxazepam 30 mg (18314). However, kava may not be effective for improving subthreshold anxiety. A meta-analysis of 3 small clinical studies in patients with subthreshold anxiety shows that taking kava does not improve anxiety symptoms when compared with placebo (110711). Overall, kava's effects appear to be dose-dependent and duration-dependent. One meta-analysis suggests that taking more than 200 mg kavalactones daily tends to be more beneficial for anxiety than taking less than 200 mg kavalactones daily (98980). Some clinical research also suggests that kava extract must be taken for at least 5 weeks to provide a benefit (2094,15046,18314,98980), while single-dose treatments may not be beneficial for acute anxiety (18319). Most studies have used a specific standardized extract (WS 1490, Dr. Willmar Schwabe Pharmaceuticals) 150-300 mg daily. Another specific kava extract (LI 150, Lichtwer Pharma) 400 mg daily has also been used (18314,98980). Clinical practice guidelines from a joint taskforce of the World Federation of Societies of Biological Psychiatry (WFSBP) and the Canadian Network for Mood and Anxiety Treatments (CANMAT) conclude that there is evidence supporting the use of kava for acute or short-term management of general anxiety symptoms but that only products standardized to a sufficient level of kavalactones should be recommended (110318).

POSSIBLY INEFFECTIVE

• Generalized anxiety disorder (GAD). Oral kava doesn't seem to be effective for treating GAD. Details: A meta-analysis of 3 small, low-quality clinical studies in adults with GAD shows that kava extract standardized to 70% kavalactones, providing 140-280 mg kavalactones daily, is no more effective than placebo when used for 4-8 weeks (15130). Additionally, a more recent meta-analysis of 3 moderate-sized clinical trials in patients diagnosed with GAD shows that taking kava does not reduce anxiety when compared with placebo or conventional therapy (110711). While a small clinical trial in adults with GAD shows that taking kava rootstock extract, standardized to provide 120-240 mg of kavalactones daily, for 6 weeks reduces clinician rated anxiety scores when compared with placebo (29663), a large, multi-center clinical trial from the same research group shows that taking kava root extract standardized to 120 mg of kavalactones twice daily for 16 weeks does not reduce anxiety scores when compared with placebo in adults diagnosed with GAD (102086). Clinical practice guidelines from a joint taskforce of the World Federation of Societies of Biological Psychiatry (WFSBP) and the Canadian Network for Mood and Anxiety Treatments (CANMAT) recommends against the use of kava rootstock extracts (standardized to 60-250 mg kavalactones) as either monotherapy or adjunctive therapy in patients with GAD (110318). This recommendation against kava for GAD is based on high quality evidence from a meta-analysis and two additional clinical trials, along with a meta-review of two meta-analyses on the use of kava for GAD (110318,112133).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Benzodiazepine withdrawal. It is unclear if oral kava is beneficial for reducing benzodiazepine withdrawal symptoms. Details: One small clinical study in patients with non-psychotic anxiety shows that titrating a specific kava extract (WS1490, Dr. Willmar Schwabe Pharmaceuticals) up to 300 mg daily over one week while tapering the benzodiazepine over 2 weeks is no more effective than placebo for decreasing benzodiazepine withdrawal symptoms (7325).
• Cancer. It is unclear if oral kava is beneficial in patients with cancer. Details: Epidemiological evidence has found that increasing kava consumption is associated with a lower incidence of cancer (8175).
• Epilepsy. Although there is interest in using oral kava for epilepsy, there is insufficient reliable information about the clinical effects of kava for this condition.
• Insomnia. It is unclear if oral kava is beneficial in patients with insomnia. Details: One small clinical study shows that taking a specific kava extract (WS1490, Dr. Willmar Schwabe Pharmaceuticals) 200 mg standardized to 70% kavalactones daily for 4 weeks reduces sleep disturbances associated with non-psychotic anxiety disorders (18321). However, another internet-based clinical trial in patients with self-reported insomnia associated with anxiety suggests that taking kava in a dose equivalent to 100 mg kavalactones three times daily for 4 weeks does not improve sleep when compared with placebo (15046).
• Menopausal symptoms. It is unclear if oral kava is beneficial for menopausal symptoms. Details: One small clinical study shows that taking kava 100-200 mg standardized to contain 55% kavaina daily for 3 months reduces depression, anxiety, and hot flashes when compared to baseline in perimenopausal patients. However, the changes in depression and hot flashes were not better when compared with the control group that took calcium (18318).
• Myalgia. Although there is interest in using oral kava for myalgia, there is insufficient reliable information about the clinical effects of kava for this condition.
• Premenstrual syndrome (PMS). Although there is interest in using oral kava for PMS, there is insufficient reliable information about the clinical effects of kava for this condition.
• Sexual arousal. Although there is interest in using oral kava for sexual arousal, there is insufficient reliable information about the clinical effects of kava for this condition.
• Stress. It is unclear if oral kava reduces reactivity to experimental stress. Details: A small study in healthy volunteers shows that taking a single dose of kava (LI 150, Lichtwer Pharma) 120 mg orally might reduce the physiological changes associated with mentally stressful tasks when compared to baseline (9893). More evidence is needed to rate kava for these uses.

(Read more about KAVA)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Age-related testosterone deficiency. It is unclear if oral maca is beneficial for age-related testosterone deficiency. Details: A moderate-size clinical study in eugonadal males age 65 years on average with symptoms related to late-onset hypogonadism shows that taking maca 1.66 grams three times daily for 12 weeks improves physical, sexual, and psychological symptom scores when compared with placebo. However, maca did not lead to a significant difference in testosterone levels between groups (112012). The interpretation of these findings is limited by the use of patient-reported outcomes.
• Amenorrhea. Although there has been interest in using oral maca for amenorrhea, there is insufficient reliable information about the clinical effects of maca for this purpose.
• Anemia of chronic disease. Although there has been interest in using oral maca for anemia of chronic disease, there is insufficient reliable information about the clinical effects of maca for this purpose.
• Antidepressant-induced sexual dysfunction. It is unclear if oral maca is beneficial in patients with sexual dysfunction due to antidepressants. Details: Preliminary clinical research shows that taking maca 1.5 grams twice daily for 12 weeks modestly increases remission rates in females experiencing antidepressant-induced sexual dysfunction (90278).
• Athletic performance. It is unclear if oral maca is beneficial for athletic performance. Details: A small clinical study in male elite athletes shows that taking maca 2500 mg twice daily for 8 weeks may improve some measures of physical performance, including grip strength, power, or agility, when compared to baseline (112014). However, the interpretation of this study is limited by the lack of a control group, inconsistent results among the various types of athletes included in the study, and unreported habitual activities, such as diet, that may confound results.
• Chronic fatigue syndrome (CFS). Although there has been interest in using oral maca for CFS, there is insufficient reliable information about the clinical effects of maca for this purpose.
• Depression. Although there has been interest in using oral maca for depression, there is insufficient reliable information about the clinical effects of maca for this purpose.
• Fatigue. Although there has been interest in using oral maca for fatigue, there is insufficient reliable information about the clinical effects of maca for this purpose.
• Leukemia. Although there has been interest in using oral maca for leukemia, there is insufficient reliable information about the clinical effects of maca for this purpose.
• Male infertility. It is unclear if oral maca is beneficial for male infertility. Details: Clinical research shows that taking a specific maca product (Maca Gelatinizada La Molina, Laboratorios Hersil) 1.5-3 grams daily for 4 months increases semen volume, sperm count, and sperm motility in healthy males aged 22-44 years (18289). Conversely, a meta-analysis of 2 small clinical studies in males with infertility shows that taking 2-2.8 grams of maca daily for 12-16 weeks does not improve the concentration of semen when compared with placebo (112011). However, the interpretation of this finding is limited by the heterogeneity of the included studies.
• Memory. Although there has been interest in using oral maca for memory, there is insufficient reliable information about the clinical effects of maca for this purpose.
• Osteoporosis. Although there has been interest in using oral maca for osteoporosis, there is insufficient reliable information about the clinical effects of maca for this purpose.
• Postmenopausal conditions. It is unclear if oral maca is beneficial for postmenopausal conditions. Details: Two small clinical trials show that taking powdered maca (Maca Power, Incan Food, Healthychoices) 3.3 or 3.5 grams daily as a single dose or in two divided doses for 6 weeks modestly reduces anxiety, depression, and sexual dysfunction when compared with placebo (90606,99792). However, these changes are generally small and of questionable clinical significance (90606).
• Sexual desire. It is unclear if oral maca improves male sexual desire; it has not been evaluated for female sexual desire. Details: Preliminary clinical research shows that taking a specific maca product (Maca Gelatinizada La Molina, Laboratorios Hersil), 1.5-3 grams daily in three divided doses for 12 weeks can increase subjective feelings of sexual desire in healthy males aged 21 to 57 years (9928).
• Tuberculosis. Although there has been interest in using oral maca for tuberculosis, there is insufficient reliable information about the clinical effects of maca for this purpose. More evidence is needed to rate maca for these uses.

(Read more about MACA)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Erectile dysfunction (ED). Preliminary clinical research in middle-aged men with ED shows that taking two capsules of a specific combination product (Revactin, MD Concepts LLC) containing muira puama, ginger root, guarana, and L-citrulline twice daily for 3 months improves scores related to erectile function and intercourse satisfaction, but does not improve sexual desire or orgasmic function scores, when compared to baseline (103224). This study is limited by the lack of a placebo control, the use of per-protocol analysis, and a high dropout rate. In fact, 44% of patients withdrew in order to resume use of phosphodiesterase type 5 (PDE5) inhibitors. Further, it is unclear if these effects are due to muira puama, other ingredients, or the combination.
• Sexual dysfunction. Preliminary clinical research in women with a low sex drive shows that taking 2-6 tablets of a specific combination product (Herbal vX) containing muira puama extract (HV-430) 350-1050 mg and ginkgo extract 32-96 mg modestly improves sexual desire and the frequency of sexual intercourse when compared with baseline (63920). The lack of control group limits the validity of these findings. Further, it is unclear if these effects are due to muira puama, ginkgo, or the combination. More evidence is needed to rate muira puama for these uses.

(Read more about MUIRA PUAMA)

LIKELY EFFECTIVE

• Dyslipidemia. Niacin prescription products, in doses of 500 mg or greater, are FDA-approved for primary hyperlipidemia and mixed dyslipidemia. Niacin dietary supplements are generally available in lower doses and have not been shown to improve lipid levels. Details: Prescription niacin is not routinely recommended as second-line therapy for patients who primarily need to decrease low-density lipoprotein (LDL) cholesterol. This is due to results from clinical trials showing no effect on cardiovascular related events or mortality (93346,93354,96208,96211,97308,97477,97336). However, niacin might be considered for patients with mixed hyperlipidemia or patients who need to increase high-density lipoprotein (HDL) cholesterol and lower triglycerides. Niacin might also be effective for isolated hypoalphalipoproteinemia (4817). The most pronounced increases in HDL and decreases in triglycerides occur at 1-1.5 grams daily, and the greatest LDL reduction occurs at 2-3 grams daily. Niacin reduces LDL cholesterol by up to 25%, compared with up to a 55% reduction with statins. High-dose niacin can also decrease triglycerides by 20% to 50%, increase HDL by 13% to 35%, decrease apolipoprotein B levels by 2% to 20%, and decrease lipoprotein(a) levels by 23% (4818,4886,4887,4888,4889,4890,12033,25567,93347,96213). The effects of higher dose extended-release niacin on LDL cholesterol and triglycerides appear to be greater in females than males (25565). Experts recommend maximizing statins first because they have the best evidence for improving cardiovascular outcomes (97477,97336,97337). However, if patients cannot reach their LDL goal with a statin alone or if they cannot tolerate a statin, niacin might be combined with other cholesterol-lowering drugs when diet and single-drug therapy are not adequately effective (8545,25566,93351,94191,97337). Adding low-dose niacin, 50 mg daily, to statin therapy has no additional benefit on lipid levels (8546). Population research in adults without dyslipidemia has also found that higher dietary intake of niacin for 3-10 years is associated with a 29% lower risk of developing dyslipidemia when compared with low dietary niacin intake (110493).
• Pellagra. Oral niacin is FDA-approved for the prevention and treatment of pellagra. Details: Population research has found that low consumption of niacin is associated with an increased risk of developing pellagra (25903). Taking niacin 500-1000 mg daily can resolve symptoms of pellagra within a week of treatment initiation (25904). However, niacinamide is sometimes preferred for this indication because it lacks the vasodilating effects of niacin (15,6243).

POSSIBLY EFFECTIVE

• HIV/AIDS-related dyslipidemia. Oral niacin seems to improve lipid levels in patients with dyslipidemia due to HIV/AIDs. Details: Small clinical trials in HIV patients with dyslipidemia associated with antiretroviral therapy shows that taking extended-release niacin (Niaspan, Abbott Laboratories) titrated up to 2 grams daily for 14-48 weeks improves total cholesterol, high-density lipoprotein (HDL) cholesterol, and triglyceride levels when compared to baseline (25570,25902). Other preliminary clinical research in this population shows that taking extended-release niacin (Niaspan, Abbott Laboratories) titrated to 2 grams daily for up to 2 years improves HDL cholesterol levels, but not total cholesterol or triglyceride levels, when compared with no treatment (25569).
• Metabolic syndrome. Oral niacin seems to improve lipid levels in patients with metabolic syndrome. Details: Clinical research shows that taking niacin (Niaspan, Abbott Laboratories) 2 grams daily orally for 16 weeks reduces triglyceride levels by 39 mg/dL and increases high-density lipoprotein (HDL) cholesterol by 5 mg/dL when compared to baseline in patients with metabolic syndrome. These improvements are significant when compared with placebo and are further increased when niacin is taken along with prescription omega-3 ethyl esters (Lovaza, GlaxoSmithKline Pharmaceuticals) 4 grams daily orally (93353). However, niacin does not seem to improve postprandial glucose levels in patients with metabolic syndrome (97333).

INEFFECTIVE

• Cardiovascular disease (CVD). Oral niacin does not seem to reduce cardiovascular-related events in patients with or without CVD. Details: Overall, niacin is not recommended for primary or secondary prevention of CVD. Most clinical trials and meta-analyses conducted prior to 2011 showed a reduction in cardiovascular-related events, cardiovascular-related mortality, and all-cause mortality in patients taking niacin alone or in combination with a statin or clofibrate for primary or secondary prevention of CVD (4847,7388,25095,25911,25912,93349). However, recent meta-analyses of these studies and additional moderate-to-high quality research conducted in over 39,000 patients show no effect of niacin on cardiovascular-related events, cardiovascular-related mortality, or overall mortality (93346,93354,96208,96211,97308). Additionally, one meta-analysis shows that patients taking niacin are twice as likely to report side effects when compared with placebo (96211). Furthermore, an analysis of blood from adults at high cardiovascular risk suggests that higher levels of circulating niacin terminal metabolites are associated with greater risk of major adverse cardiovascular events independent of traditional risk factors (113554).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Alzheimer disease. It is unclear if oral niacin is beneficial for reducing Alzheimer disease risk. Details: Observational research has found that consuming higher amounts of niacin (17-45 mg daily) from food and supplements is associated with a slower cognitive decline and a lower risk of developing Alzheimer disease when compared with people who consume less niacin (14 mg daily) (12077). It is not known if the risk of Alzheimer disease is reduced by taking a stand-alone niacin supplement.
• Atherosclerosis. It is unclear if oral niacin prevents atherosclerosis progression. Details: Preliminary clinical studies show that taking niacin orally, in combination with colestipol for up to 2 years, might modestly reduce progression of atherosclerosis as measured by coronary lesions and carotid arterial intima-media thickness in high-risk males with existing coronary atherosclerosis (25906,25909,25910). However, niacin does not seem to be better than statins. One clinical study in adults with atherosclerosis and peripheral arterial disease shows that taking extended-release niacin 1500 mg, simvastatin 40 mg, and ezetimibe 10 mg daily for 2 years does not reduce atherosclerosis of the superficial femoral artery when compared with simvastatin alone (96208). Niacin has also not been shown to prevent cardiovascular events or mortality (93346,93354,96208,96211,97308).
• Athletic performance. It is unclear if oral niacin improves athletic performance. Details: Preliminary clinical research in untrained adult males shows that taking niacin 1000 mg orally once before a cycling test does not improve power, respiratory exchange ratio, or time to exhaustion when compared with placebo. In addition, these measures were significantly worse when compared with taking caffeine 5 mg/kg orally as a single dose (107942). Clinical research in untrained males also shows that taking a supplement containing niacin 40 mg, caffeine 400 mg, capsicum extract 66.7 mg, and black pepper extract 10 mg prior to exercising does not improve strength, time to exhaustion, or maximal oxygen consumption when compared with placebo (37873).
• Attention deficit-hyperactivity disorder (ADHD). Although there is interest in using oral niacin for ADHD, there is insufficient reliable information about the clinical effects of niacin for this condition.
• Cancer. It is unclear if dietary niacin is beneficial for cancer. Details: Population research in adults with cancer has found that high dietary niacin intake is associated with 49% and 27% lower risk of cancer-related mortality and all-cause mortality when compared with low dietary niacin intake. The same study also found that taking niacin supplements is associated with a lower risk of cancer-related mortality, but not all-cause mortality when compared with not taking niacin supplements (110496).
• Cataracts. It is unclear if oral niacin is beneficial for preventing cataracts. Details: Population research has found that high dietary intake of niacin is associated with a reduced risk of nuclear cataracts (6378). However, there is no reliable evidence that niacin supplements reduce the risk of cataracts.
• Cholera. It is unclear if oral niacin is beneficial for cholera. Details: One small clinical study in adults with severe cholera shows that taking 1-2 grams niacin orally reduces fluid loss in the stool by 31% to 47% in the first 16 hours when compared with control. The 2 gram dose seemed to result in a greater reduction in fluid loss than the 1 gram dose (4868).
• Erectile dysfunction (ED). It is unclear if oral niacin is beneficial in patients with ED and dyslipidemia. Details: Clinical research in patients with erectile dysfunction and dyslipidemia shows that taking extended-release niacin (Niaspan, Abbott Laboratories) titrated to 1.5 grams nightly for a total of 12 weeks significantly improves penetration frequency and the maintenance of an erection after penetration when compared to baseline (25913). The validity of this finding is limited by the lack of a comparator group.
• Glaucoma. It is unclear if oral niacin is beneficial for preventing or treating glaucoma. Details: Population research has found that higher dietary intake of niacin is associated with a lower odds of having glaucoma. However, this association was not consistently present when adjusting for confounders. The effects of niacin supplementation on glaucoma have not been evaluated (107942).
• Hyperphosphatemia. It is unclear if oral niacin is beneficial for preventing high levels of phosphorus in the blood. Details: Preliminary clinical research in patients on maintenance dialysis who are no longer using phosphate binders shows that taking niacin 375-750 mg daily for 8 weeks reduces serum phosphorus levels by 2.1 mg/dL, increases calcium levels by 0.4 mg/dL, and decreases serum alkaline phosphatase when compared with baseline (25914). However, clinical research in hemodialysis patients with inadequate phosphate control despite using standard phosphate-binding therapy shows that taking niacin at the maximum tolerated dose, up to 1000 mg daily, for 12 weeks, does not decrease serum phosphate levels when compared with placebo (93341). It is possible that this latter study was too small to observe between-group differences in changes in serum phosphate levels.
• Hypertension. It is unclear if dietary niacin is beneficial for preventing hypertension. Details: Observational research in Chinese adults found a J-shaped association between dietary niacin intake and development of hypertension, with the lowest risk occurring in those with a daily dietary niacin intake of 14.3-16.7 mg (104934).
• Meniere disease. Although there is interest in using oral niacin for Meniere disease, there is insufficient reliable information about the clinical effects of niacin for this condition.
• Migraine headache. It is unclear if dietary niacin is beneficial for preventing migraine headaches. Details: Population research in adults has found that high dietary intake of niacin is associated with a 28% lower likelihood of having migraine headaches when compared with low dietary intake of niacin (110495). However, the effect of niacin supplementation on migraines has not been studied.
• Motion sickness. Although there is interest in using oral niacin for motion sickness, there is insufficient reliable information about the clinical effects of niacin for this purpose.
• Parkinson disease. It is unclear if oral niacin is beneficial for improving Parkinson disease symptoms. Details: Low-quality clinical research in adults with Parkinson disease shows that taking slow-release niacin 250 mg orally daily for 12 months improves Parkinson disease motor scores and fatigue scores by 17% and 26%, respectively, when compared with baseline (107944). However, higher quality clinical research shows that taking niacin 250 mg orally daily for 6 months does not improve Parkinson disease motor scores when compared with placebo (107943).
• Retinal vein occlusion. It is unclear if oral niacin is beneficial for improving retinal vein occlusion symptoms. Details: A small case series in patients with chronic retinal vein occlusion shows that taking niacin titrated to 500 mg three times daily for 1 year is associated with reduced central macular thickness and improved visual acuity in over 50% of patients when compared with a control group. The addition of prednisolone eye drops does not alter the outcomes of those taking niacin (96212). The validity of this finding is limited due to the retrospective nature of this study.
• Sickle cell disease. It is unclear if oral niacin is beneficial for improving lipid levels in patients with sickle cell disease. Details: A small clinical study in patients with sickle cell disease shows that taking extended-release niacin titrated to 1.5 grams daily for 12 weeks does not improve vascular function or increase high-density lipoprotein (HDL) or apolipoprotein A-I cholesterol levels when compared with placebo (96209).
• Schizophrenia. Although there is interest in using oral niacin for schizophrenia, there is insufficient reliable information about the clinical effects of niacin for this condition.
• Vertigo. Although there is interest in using oral niacin for vertigo, there is insufficient reliable information about the clinical effects of niacin for this condition. More evidence is needed to rate niacin for these uses.

(Read more about NIACIN)

LIKELY EFFECTIVE

• Coronary heart disease (CHD). A diet high in soluble fiber, such as that found in oats, reduces the risk of CHD. Details: Clinical research shows that a diet containing foods high in fiber, such as oats, oat bran, or whole oat flour, reduces the risk of CHD (2737,4960,4962,4963,4964,4965,4966,4967,4968). In 1993, the US Food and Drug Administration (FDA) approved a health claim stating that consuming at least 3 grams of soluble fiber per day, as part of a diet low in saturated fat and cholesterol, may reduce the risk of CHD (102336). However, clinical studies show that at least 3.6 grams of soluble fiber daily is needed to reduce the risk of CHD (5786,5787,5788,5794,5795,5796).
• Dyslipidemia. A diet rich in soluble fiber, such as that found in oats, can reduce cholesterol by a moderate amount. Details: Oats, oat bran, and other soluble fibers can modestly reduce total and low-density lipoprotein (LDL) cholesterol, especially when consumed as part of a diet low in saturated fat. Consuming 56-150 grams of whole oat products such as oatmeal and oat bran, containing 3.6-10 grams of soluble fiber daily, can significantly lower total and LDL cholesterol levels. For each gram of soluble fiber consumed, total cholesterol decreases by about 1.4 mg/dL and LDL by about 1.2 mg/dL. Eating 3-10 grams of soluble fiber daily can reduce total cholesterol by about 4-14 mg/dL (4976,4977,5786,5788,5792,5794,5795,8521,107749,113488,113495). For example, eating 3 bowls of oatmeal (28 gram servings) daily, providing a total of 3 grams of soluble fiber daily, can decrease total cholesterol by about 5 mg/dL (5788). However, consuming more than 10 grams of soluble fiber daily doesn't seem to increase effectiveness (5788). A meta-analysis comparing the effects of oats and isolated beta-glucans shows that both products similarly impact lipid profiles, suggesting that the bioactive component of oats are beta-glucans (113488). Oat bran products, such as oat bran muffins and oat bran flakes, may vary in their ability to lower cholesterol, depending on the total soluble fiber content and other dietary variables (6188). Whole oat products might be more effective for lowering LDL and total cholesterol than foods containing oat bran plus soluble fiber (10145). Although oats are shown to lower total and LDL cholesterol, a meta-analysis and a small clinical study in adults with and without dyslipidemia shows that consuming oatmeal or oat products does not reduce triglycerides or increase high-density lipoprotein (HDL) cholesterol when compared with controls (113488,113495).

POSSIBLY EFFECTIVE

• Diabetes. A diet rich in whole grains, such as oats, may help prevent diabetes or improve blood glucose control in patients with type 1, type 2, or gestational diabetes. Details: Population research shows that for every 16 gram daily serving of whole grains, including oats, there is a 7% to 11% lower risk of developing type 2 diabetes (100622). There is also evidence that consuming oats can decrease blood glucose and insulin levels, as well as lipid levels, in patients with diabetes. The glycemic effects of oats depend on the level of processing of the oat products. Consuming intact oat kernels or thick-cut oats (>0.6 mm) reduces postprandial blood glucose and insulin, but consuming thin-cut, or "quick", oats has no effect (105536). Clinical research shows that consuming oats and oat bran for 4-8 weeks decreases pre-prandial blood glucose, 24-hour plasma glucose, glycated hemoglobin (HbA1c), insulin levels, and low-density lipoprotein (LDL) cholesterol in people with type 2 diabetes (4980,4982,6266,103345). Various doses have been used, including 3 grams of soluble fiber daily, or bread providing 34 grams of total fiber daily (9 grams of soluble fiber) (4961,4980). Additional clinical research in obese adults with type 2 diabetes shows that eating whole grain oats 50-100 grams daily in place of other carbohydrates reduces postprandial blood glucose by 19-27 mg/dL when compared with other carbohydrates in a healthy diet. After 1 year, the groups consuming 50 grams and 100 grams of oats had an additional 0.48% and 0.64% reduction in HbA1c, respectively, when compared with the regular healthy diet group (97520). There is also some evidence that consuming oats 50 grams daily, containing 25 grams of soluble fiber, might be more effective for improving glycemic control and decreasing hyperinsulinemia than the standard moderate fiber diet recommended by the American Diabetes Association (ADA) (6266). Oats have also been evaluated in adolescents with type 1 diabetes. One very small clinical study shows that taking 50 grams of a specific oat product (Betaglucare), providing beta-glucans 6 grams, in three divided doses daily for one week is beneficial for glycemic control and variability when compared with a standard diet without beta-glucans or with taking only 25 grams of the product daily. Maximal, mean, and pre- and post-meal blood glucose levels were modestly lower, and minimal blood glucose levels were modestly higher. Most measures of glycemic variability were statistically different, although there were no differences in the duration of hypoglycemia or hyperglycemia between groups (105261). Oats have also been evaluated in patients with gestational diabetes. A randomized, controlled trial shows that taking 30 grams of a specific oat bran product (OAB; Golden Light Cup Company) orally twice daily at lunch and dinner for 4 weeks improves mean fasting blood glucose and two-hour postprandial glucose when compared with a control group. After 4 weeks, the mean fasting blood glucose and 2-hour postprandial glucose in the treatment group were 85 mg/dL and 104 mg/dL, respectively, compared with 93 mg/dL and 117 mg/dL, respectively, in the control group (107751). The validity of this study is limited by the short treatment duration and lack of follow-up.
• Gastric cancer. A diet rich in soluble fiber, such as that found in oats, might reduce the risk of gastric cancer. Details: Observational research has found that consuming a diet that includes cereal fiber, such as oats and oat bran, might reduce the incidence of gastric cancer (10435).

POSSIBLY INEFFECTIVE

• Colorectal cancer. Regular consumption of oats does not seem to reduce the risk of colorectal cancer. Details: Observational research has found that consuming oat bran or oats orally doesn't seem to reduce the risk of colon cancer. Additionally, consuming fiber, including oat-bran fiber, is not associated with a reduction in the risk for recurrence of colorectal adenomas (4820,5104).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acne. Although there is interest in using topical oats for acne, there is insufficient reliable information about the clinical effects of oats for this purpose.
• Anxiety. Although there is interest in using oral oats for anxiety, there is insufficient reliable information about the clinical effects of oats for this purpose.
• Atopic dermatitis (eczema). Topical colloidal oatmeal cream may be beneficial in patients with atopic dermatitis. Details: Preliminary clinical research shows that applying a cream containing colloidal oatmeal 1% daily for 2 weeks moderately reduces the severity of atopic dermatitis when compared with baseline (103344). The validity of this finding is limited by the lack of a comparator group. Other research suggests that colloidal oatmeal may be beneficial when used in combination with topical steroids. Clinical research shows that the benefits obtained from applying an ointment containing fluocinolone 0.025% to the hands for 2 weeks were better maintained in the patients who also used a cream containing colloidal oatmeal 1% during this time period and for an additional 4 weeks when compared with patients using fluocinolone and the cream base without colloidal oatmeal. Quality of life was also improved in the patients using colloidal oatmeal (103340).
• Breast cancer. Observational research suggests that regular oatmeal intake may be associated with reduced mortality from breast cancer. Details: Population research in postmenopausal patients has found that those who have eaten 50 grams of oatmeal daily prior to a breast cancer diagnosis have a 20% reduced risk of all-cause mortality in the 7 years following the diagnosis when compared with patients who have not eaten oatmeal. However, no benefit was seen when post-diagnostic oatmeal intakes were examined (103343).
• Burns. Although there is interest in using topical oats for burns, there is insufficient reliable information about the clinical effects of oats for this purpose.
• Chronic fatigue syndrome (CFS). Although there is interest in using oral oats for CFS, there is insufficient reliable information about the clinical effects of oats for this purpose.
• Cognitive function. It is unclear if oral oats are beneficial in healthy adults with mild memory impairment. Details: Preliminary clinical research in healthy middle-aged adults with self-reported memory decline shows that consuming a specific wild green-oats extract (Neuravena, Frutarom) 800 mg as a single dose improves overall speed, but not overall accuracy, of cognitive performance when compared with placebo. However, a higher dose of 1600 mg was ineffective (97519).
• Dry skin. It is unclear if applying lotion containing colloidal oat extract improves dry skin to a greater extent than other lotion products. Details: Preliminary clinical research shows that applying a lotion containing colloidal oat extract (Aveeno Active Naturals Skin Relief 24Hr Moisturizing Lotion, Johnson & Johnson) twice daily for 2 weeks improves itchiness, cracking, scaling, dryness, and roughness when compared to baseline in females with dry skin (91458). Additional preliminary clinical research shows that applying a colloidal oatmeal lotion to the legs twice daily for three weeks reduces skin dryness and improves skin integrity when compared to baseline in adults with dry skin (97518). The validity of these findings is limited by the lack of a comparator group.
• Exercise-induced muscle soreness. It is unclear if oral oats are beneficial for exercise-induced muscle soreness. Details: A small clinical trial shows that eating two cookies containing oat flour 60 grams daily for 8 weeks reduces muscle soreness 48 or 72 hours after downhill running when compared with baseline (103341).
• Fat redistribution syndrome. It is unclear if oral oats are beneficial for fat redistribution syndrome. Details: Consumption of a high fiber diet, including oats, with adequate energy and protein might prevent fat deposition in patients with HIV. A one-gram increase in total dietary fiber may decrease the risk of fat deposition by 7% (12517).
• Gallbladder disease. Although there is interest in using oral oats for gallbladder disease, there is insufficient reliable information about the clinical effects of oats for this purpose.
• Hypertension. It is unclear if oral oats are beneficial for hypertension. Details: A meta-analysis of 21 clinical studies in healthy adults and those with a variety of metabolic conditions including hypertension shows that consumption of oat products reduces systolic blood pressure (SBP) by 3 mmHg but has no effect on diastolic blood pressure (DBP) when compared with control. Subgroup analysis suggests that consuming oat products reduces SBP by 10 mmHg in patients with hypertension at baseline. An additional subgroup analysis suggests that consuming at least 5 grams of beta-glucan-enriched oats daily or consuming oats for a duration at least 8 weeks reduces SBP and DBP (113494). Observational research has found that consumption of oats as oatmeal or oat cereal does not seem to reduce DBPor SBP in males with minor elevations in blood pressure or patients with dyslipidemia (2956,113495). A randomized, controlled trial in patients with stage 1 hypertension receiving dietary guidance shows that taking 30 grams of oat bran, providing 8.9 grams of dietary fiber, once daily with breakfast or in between meals for 3 months improves various blood pressure measures when compared with dietary guidance alone. After 3 months of treatment, 24-hour maximum SBP and DBP decreased by 14 mmHg and 11 mmHg, respectively, and office SBP and DBP decreased by 15 mmHg and 10 mmHg, respectively. Oat consumption may also have impacted antihypertensive medication use. Two patients in the control group increased doses of antihypertensive medications, whereas 6 patients in the treatment group decreased doses and 1 patient discontinued use (107750). The effect of oral oat bran on patients with stage 2 hypertension or pre-hypertension is unknown.
• Irritable bowel syndrome (IBS). Although there is interest in using oral oats for IBS, there is insufficient reliable information about the clinical effects of oats for this purpose.
• Metabolic syndrome. Limited research suggests that oats may not be beneficial for metabolic syndrome. Details: Preliminary clinical research in adults with metabolic syndrome shows that adding oat bran 40 grams daily for 6 weeks to a low-calorie diet does not reduce the incidence of metabolic syndrome. Oat bran also does not improve body weight, blood pressure, low-density lipoprotein (LDL) cholesterol, triglycerides, or blood glucose levels when compared with a low-calorie diet alone in patients with metabolic syndrome (103342).
• Osteoarthritis. Although there is interest in using oral oats for osteoarthritis, there is insufficient reliable information about the clinical effects of oats for this condition.
• Pruritus. Applying oat lotion topically may improve some types of pruritus. Details: Preliminary clinical research shows that applying an oat lotion (Espanol) twice daily for up to 2 weeks can decrease itching intensity by about 20% when compared to baseline in patients with pruritus associated with chronic kidney disease (uremic pruritus). This decrease is similar to the effects of applying vinegar 5% solution or taking hydroxyzine 10 mg orally. However, applying the oat lotion does not appear to decrease the frequency of itching (91457).
• Psoriasis. Although there is interest in using topical oats for psoriasis, there is insufficient reliable information about the clinical effects of oats for this purpose.
• Rheumatoid arthritis (RA). Although there is interest in using oral oats for RA, there is insufficient reliable information about the clinical effects of oats for this purpose.
• Stroke. It is unclear if oral oats are beneficial for reducing the risk of stroke. Details: Population research suggests that consuming oatmeal for breakfast once weekly might reduce the incidence of stroke by a small amount when compared with consuming white bread or eggs for breakfast (103337).
• Ulcerative colitis. Oral oats have only been evaluated in combination with other ingredients; their effect when used alone is unclear. Details: Preliminary clinical research shows that taking a specific oat-based product (Profermin, Nordisk Rebalance) containing fermented oat flour, Lactobacillus plantarum, barley malt flour, and lecithin, 250 mL orally twice daily for 8 weeks, reduces disease activity and increases remission in about two-fold more patients with relapsing ulcerative colitis, when compared with treatment with a specific nutritional beverage (Fresubin Original, Fresenius Kabi) (90271).
• Wound healing. Although there is interest in using topical oats for wound healing, there is insufficient reliable information about the clinical effects of oats for this purpose. More evidence is needed to rate oats for these uses.

(Read more about OATS)

LIKELY EFFECTIVE

• Depression. Specific formulations of oral St. John's wort are effective for mild or moderate major depressive disorder. St. John's wort may also cause fewer side effects than certain conventional antidepressants. Details: Moderate quality meta-analyses and individual clinical trials show that St. John's wort extracts are more effective than placebo (76057,76140,76143,76271,89669,104036), and likely as effective as low-dose tricyclic antidepressants (6434,76143), tetracyclic antidepressants (76174), and selective serotonin reuptake inhibitors (SSRIs) (76143,76144,96551), including fluoxetine (Prozac) (3550,4897), sertraline (Zoloft) (6400), and paroxetine (Paxil) (13021) for treating depression. However, some of these studies have been critiqued for using lower doses of SSRIs than typical dosing in comparative studies (104037). St. John's wort also seems to have better tolerability and less gastrointestinal, neurologic, and sexual adverse effects than certain conventional antidepressants (104036). Taking St. John's wort extract improves mood and decreases anxiety, somatic symptoms, and insomnia related to mild to severe major depression (3550,4897,6400,13021,13157,76143,104036). Short-term response rates to St. John's wort appear to be between 65% and 100%; however, long-term, the response rates appear to range from 60% to 69% (13156). Most studies have evaluated St. John's wort in adults; however, there is also some evidence that taking St. John's wort 300-1800 mg daily might be effective for depression in children less than 17 years old (4538,10844,76110). There is some concern that St. John's wort may not be effective for severe major depressive disorder necessitating psychiatric care. Two studies in psychiatric care settings showed no benefit of using St. John's wort (5096,10843). Clinical guidelines from the American College of Physicians state that St. John's wort may be as effective and better tolerated than conventional antidepressants for mild to moderate depression (104037). Guidelines from The World Federation of Societies of Biological Psychiatry (WFSBP) and Canadian Network for Mood and Anxiety Treatments (CANMAT) Taskforce state that St. John's wort is recommended as monotherapy for mild to moderate forms of major depressive disorder (110318). There is no guarantee that people living in the United States can obtain St. John's wort preparations of similar potency and effectiveness as those used in clinical research (104037). The CANMAT Taskforce recommendation is for specific formulations of 3:1 to 7:1 extracts, standardized to approximately 0.2-0.3% hypericin and/or 5-6% hyperforin, in single or divided doses of 600 mg to 1800 mg daily (110318). Most studies have used St. John's wort extracts standardized to hypericin content, usually 0.3%, but extracts standardized to 1% to 4% hyperforin also seem to be effective. Extracts containing hypericin 0.2% to 0.3%, including LI 160 (Lichtwer Pharma) and Remotiv (Zeller) have most often been studied in doses of 300 mg three times daily for up to 6 weeks, or 250 mg twice daily for up to 6 weeks. Extracts containing 3% to 6% hyperforin, including Movana (Pharmaton) and WS 5570 (Schwabe Pharmaceuticals) have most often been studied in doses of 300-600 mg three times daily for 6-26 weeks (761,4538,4630,104036).

POSSIBLY EFFECTIVE

• Menopausal symptoms. Oral St. John's wort seems to be beneficial for patients with menopausal symptoms. Details: Most clinical research shows that taking St. John's wort as a single supplement can reduce menopausal symptoms. A meta-analysis of small clinical trials in menopausal adults shows that taking St. John's wort up to 900 mg daily for up to 16 weeks, alone or in combination with other herbs, reduces frequency and severity of hot flashes when compared with placebo (95510). Some research also suggests that St. John's wort might improve quality of life and psychological symptoms when compared with placebo (76043,76146,89666,95510). St. John's wort has also shown benefit when used in combination with black cohosh (Remifemin Plus, Schaper & Brummer GmbH & Co. KG; Gynoplus, Jin-Yang Pharm; Feramin Q, Dongkook Pharm) (15037,15893,35853,95510), and with Vitex agnus-castus (41482).
• Somatic symptom disorder. Oral St. John's wort seems to be beneficial for patients with somatoform disorder. Details: Two clinical trials in patients with somatoform disorders shows that taking a specific standardized St. John's wort extract (LI 160, Lichtwer Pharma) 600 mg daily seems to reduce symptoms of somatization disorder by 45% after 6 weeks of treatment when compared with placebo (9476,76089).

POSSIBLY INEFFECTIVE

• Burning mouth syndrome. Oral St. John's wort does not appear to reduce pain from burning mouth syndrome. Details: A small clinical study in patients with burning mouth syndrome shows that taking St. John's wort 300 mg (standardized to hypericin 0.3% and hyperforin 3.0%) three times daily for 12 weeks does not alleviate pain when compared to placebo (76133).
• Hepatitis C. St. John's wort contains hypericin. Synthetic hypericin has been studied and shown to be ineffective as an oral drug for hepatitis C. Details: A small clinical study in patients with chronic hepatitis C virus (HCV) infection shows that giving synthetic hypericin 0.05-0.1 mg/kg orally daily does not seem to be effective for reducing viral load and may be unsafe due to the risk for phototoxic reactions (4631).
• HIV/AIDS. St. John's wort contains hypericin. Synthetic hypericin has been studied and shown to be ineffective as an oral and intravenous drug for HIV. Details: A small clinical study in adults infected with HIV shows that giving synthetic hypericin 0.25-0.5 mg/kg, either intravenously 2-3 times weekly or orally every day, as an antiretroviral agent does not seem to be effective and may be unsafe due to the risk for phototoxic reactions, which occurred in about 50% of patients (206).
• Irritable bowel syndrome (IBS). Oral St. John's wort does not seem to improve symptoms in patients with IBS. Details: A small clinical study shows that taking a specific St. John's wort extract (St. John's Wort Extract Extra Strength, Enzymatic Therapy) 450 mg twice daily is no more effective than placebo for reducing symptoms of IBS after 12 weeks of treatment. In fact, patients taking placebo had improved symptoms compared to St. John's wort (16893).
• Peripheral neuropathy. Oral St. John's wort does not seem to relieve pain in patients with peripheral neuropathy. Details: A small clinical study in diabetic and non-diabetic patients with polyneuropathy shows that taking St. John's wort containing 0.9 mg hypericin orally daily for 5 weeks does not seem to relieve most measures of pain when compared with placebo (7047).
• Social anxiety disorder. Oral St. John's wort does not seem to be beneficial for patients with social anxiety disorder. Details: A small clinical study shows that taking St. John's wort 600-1800 mg daily for 12 weeks does not improve social phobia or social anxiety disorder when compared with placebo (76101).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acne. It is unclear if topical St. John's wort is beneficial for acne. Details: A small clinical trial in patients with mild to moderate acne treated with photodynamic therapy shows that topical application with 1.5 mL of a St. John's wort 0.5% extract (DR-Light complex; Genicos Co., Ltd, Cheongju, Korea) for 10 minutes for four weekly sessions reduces acne lesion count as effectively as treatment with indole-3-acetic acid (110327).
• Anxiety. Although there is interest in using oral St. John's wort for anxiety, there is insufficient reliable information about the clinical effects of St. John's wort for this condition.
• Attention deficit-hyperactivity disorder (ADHD). It is unclear if oral St. John's wort is beneficial for improving symptoms in children with ADHD. Details: A small clinical study in children ages 6-17 years with ADHD shows that taking a specific St. John's wort extract standardized to 0.3% hypericin, 300 mg three times daily for 8 weeks, does not improve symptoms such as inattentiveness when compared with placebo (17986).
• Brain tumor. St. John's wort contains hypericin. Synthetic hypericin has been studied as an oral drug for malignant brain tumors, with unclear benefit. Details: A small clinical study in patients with malignant gliomas shows that taking synthetic hypericin 0.05-0.5 mg/kg daily orally for up to 3 months was associated with stable disease in 7 of 42 patients and partial response in 2 of 42 patients (76160). However, it is unclear how these outcomes would compare with historical controls or a prospectively enrolled control group.
• Chronic fatigue syndrome (CFS). Although there is interest in using oral St. John's wort for CFS, there is insufficient reliable information about the clinical effects of St. John's wort for this condition.
• Crigler-Najjar syndrome type 2. It is unclear if oral St. John's wort is beneficial for patients with this condition. Details: Crigler-Najjar syndrome type 2 is a rare genetic disorder characterized by the accumulation of bilirubin in the body. One case report of a 24 year-old female with this condition shows that taking St. John's wort (Jarsin LI160, Vifor SA) 300 mg three times daily by mouth for two 8-week periods 18 months apart decreases bilirubin levels by 34%, reduces jaundice, and improves fatigue (95509).
• Fibromyalgia. Although there is interest in using oral St. John's wort for fibromyalgia, there is insufficient reliable information about the clinical effects of St. John's wort for this condition.
• Genital herpes. Topical St. John's wort has only been evaluated in combination with copper sulfate; its effect when used alone is unclear. Details: A clinical study in patients with herpes simplex virus 1 (HSV-1) or 2 (HSV-2) shows that applying a single dose of a specific topical product (Dynamiclear, Global Herbal Supplies Pty Ltd), which contains St. John's wort 0.1% and copper sulfate pentahydrate 5%, helps reduce symptoms such as stinging, burning, erythema, and pain. In fact, the combination product appears to reduce erythema, itching, and pain more than applying acyclovir 5% (Zovirax, Glaxo Smith Kline) five times daily for 7 days (76164).
• Herpes labialis (cold sores). Topical St. John's wort has only been evaluated in combination with copper sulfate; its effect when used alone is unclear. Details: A clinical study in patients with herpes simplex virus 1 (HSV-1) or 2 (HSV-2) shows that applying a single dose of a specific topical product (Dynamiclear, Global Herbal Supplies Pty Ltd), which contains St. John's wort 0.1% and copper sulfate pentahydrate 5%, helps reduce symptoms such as stinging, burning, erythema, and pain. In fact, the combination product appears to reduce erythema, itching, and pain more than applying acyclovir 5% (Zovirax, Glaxo Smith Kline) five times daily for 7 days (76164).
• Mastitis. It is unclear if topical St. John's wort is beneficial for granulomatous mastitis. Details: In patients with idiopathic granulomatous mastitis, persistent or intractable skin lesions may remain after treatment with oral steroids and antibiotics. Preliminary clinical research shows that topical application with St. John's wort oil for two minutes twice daily for 6 weeks reduces the severity of skin lesions in patients with persistent lesions following treatment. After treatment, the success rate, based on clearance or remaining mild symptoms, was 94.1% (110326).
• Memory. It is unclear if oral St. John's wort is beneficial for improving memory in healthy people. Details: A small clinical study in healthy adults shows that taking a specific supplement (Remotiv, Zeller) containing St. John's wort 250 mg, standardized to 0.5 mg of hypericin, by mouth as a single dose, seems to improve short-term memory when compared with baseline. In contrast, the same product containing a higher dose of St. John's wort, 500 mg, seems to worsen memory when compared with baseline (100245). The validity of this finding is limited by the lack of a control group.
• Migraine headache. It is unclear if oral St. John's wort is beneficial for reducing migraine headache. Details: A small low quality clinical study in patients with migraines suggests that adding a specific St. John's wort product (Perforan, Godaru) 160 mg three times daily to sodium valproate 400 mg daily might modestly improve migraine intensity, but not migraine frequency, when compared with sodium valproate alone (89667).
• Obsessive-compulsive disorder (OCD). It is unclear if oral St. John's wort is beneficial for reducing OCD symptoms. Details: There is conflicting evidence about the effectiveness of St. John's wort for OCD. A small open-label study suggests that taking a specific St. John's wort extract standardized to 0.3% hypericin (Alterra, Upsher-Smith Laboratories) 450 mg twice daily for 12 weeks might improve symptoms of OCD when compared to baseline (5075). The validity of this finding is limited by the lack of a control group. A small, higher quality clinical study using a different St. John's wort extract (LI 160, Lichtwer Pharma AG) 600-1800 mg daily for 12 weeks shows that it does not improve symptoms of OCD when compared with placebo (14417). However, this study excluded patients with concomitant depression, so it's unclear if St. John's wort might improve OCD symptoms in patients with depression.
• Osteoarthritis. It is unclear if topical St. John's wort is beneficial for osteoarthritis. Oral St. John's wort is not studied for this use. Details: A moderate-sized clinical study in adults with knee osteoarthritis shows that applying St. John's wort oil (concentration unknown) to the knees three times a day for 21 days improves patient-reported pain, stiffness, and function scores when compared with placebo (olive oil) (113093). However, participants were aware of which treatment they received and were allowed to continue use of analgesics as needed, which limits the validity of this study.
• Polycystic ovary syndrome (PCOS). Oral St. John's wort has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study shows that taking three tablets containing St. John's wort, licorice root, Ceylon cinnamon, levant berry, peony, and Tribulus daily for 3 months, in addition to lifestyle changes, improves oligomenorrhea by 33% and quality of life by 30% when compared with lifestyle changes alone in adults with PCOS (97216). It is unclear if these effects are due to St. John's wort, other ingredients, or the combination.
• Premenstrual syndrome (PMS). It is unclear if oral St. John's wort is beneficial for patients with PMS. Details: There is conflicting evidence on the effects of St. John's wort for treating PMS, although most evidence suggests benefit. A small clinical study shows that taking a specific St. John's wort extract standardized to contain 0.18% hypericin and 3.38% hyperforin (LI 160, Lichtwer Pharma AG) 450 mg twice daily for two menstrual cycles reduces physical and behavioral PMS symptoms, but not mood or pain, when compared with placebo (76150). Another clinical study shows that taking St. John's wort extract containing hypericin 1.36 mg daily for two menstrual cycles can reduce symptoms of PMS, including anxiety, depression, forgetfulness, crying, headache, and fatigue, when compared with placebo (76159). However, one clinical study shows that taking St. John's wort 600 mg (standardized to contain 1.8 mg of hypericin) does not reduce anxiety or other PMS symptoms when compared with placebo (76104). The conflicting results may be due to differences in St. John's wort formulations and dosages.
• Psoriasis. It is unclear if topical St. John's wort improves symptoms in patients with plaque psoriasis. Details: A small clinical study in patients with mild or moderate plaque psoriasis shows that applying an ointment containing St. John's wort extract 5% twice daily to one side of the body for 4 weeks modestly decreases the severity, thickness, and degree of erythema of psoriasis plaques when compared with applying placebo ointment to the other side of the body (95940).
• Seasonal affective disorder (SAD). It is unclear if oral St. John's wort is beneficial for patients with SAD. Details: Preliminary clinical research shows that St. John's wort extract improves symptoms associated with SAD, including anxiety, decreased libido, and sleep disturbances, when compared with baseline. It may be beneficial when used alone or in combination with light therapy (9686,76175). However, the validity of these findings is limited by the lack of a comparator group.
• Scleroderma. Topical St. John's wort has only been evaluated in combination with neem oil; its effect when used alone is unclear. Details: A small observational study in patients with systemic sclerosis has found that topical application of a specific cream (Holoil, RI.MOS. SRL) containing St. John's wort and neem oil is associated with improved healing, decreased pain, and reduced need for surgical interventions and antibiotics when compared with a control group (102867). It is unknown if these effects are due to St. John's wort, neem, or the combination. Additionally, the validity of these results is limited by a lack of randomization, blinding, and placebo-control.
• Smoking cessation. It is unclear if oral St. John's wort is beneficial for patients trying to quit smoking. Details: A small clinical study in cigarette smokers shows that taking a specific St. John's wort extract (LI-160, Lichtwer Pharma US) 300 mg once or twice daily, starting 1 week before and continuing for 3 months after quitting smoking, is associated with a continuous abstinence rate of 18% at 3 months and 0% at 12 months, suggesting a lack of benefit (14481).
• Wound healing. Topical St. John's wort seems to improve wound healing and wound-related pain for certain types of surgery. Details: A clinical study in patients who have had a Cesarean section shows that applying ointment containing St. John's wort extract 20% three times a day for 16 days improves wound healing and reduces scar formation when compared with placebo ointment (17225). Preliminary clinical research in patients who have had impacted third molars removed shows that using a mouthwash, prepared by macerating the above ground parts of St. John's wort in virgin olive oil, for 60 days is as effective as chlorhexidine gluconate plus benzydamine hydrochloride mouthwash for improving periodontal healing, and reducing swelling, pain, and infectious complications. However, it was also as effective as plain virgin olive oil, suggesting that St. John's wort did not provide additional benefit. 15 mL of each mouthwash was swished for 30 seconds 3 times daily for 7 days (104957). St. John's wort has also been evaluated in combination with other ingredients. A moderate-sized clinical study in adults with dehisced post-surgical wounds shows that applying a specific aerosol product (1PWD, Kerecis AG) containing St. John's wort and neem oil to wounds during dressing changes does not improve wound healing scores at day 28 but may reduce pain scores when compared with silver-based dressings (alginates or polyurethane foam) (111592). However, this study may have been inadequately powered to detect a difference between groups. It is also unclear if these effects are due to St. John's wort, neem oil, or the combination.
• Tinnitus. St. John's wort has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small study in adults with tinnitus shows that taking St. John's wort 600 mg and ginkgo biloba daily for 12 weeks does not suppress tinnitus or improve tinnitus-related handicap when compared with ginkgo biloba monotherapy (111513). More evidence is needed to rate St. John's wort for these uses.

(Read more about ST. JOHN'S WORT)

POSSIBLY EFFECTIVE

• Sexual dysfunction. Oral tribulus seems to improve sexual experience in females with hypoactive sexual desire disorder (HSDD) or sexual dysfunction. Some research also shows that oral tribulus improves sexual function in males. Details: Clinical research in premenopausal and postmenopausal patients with HSDD shows that taking tribulus 250 mg three times daily (Androsten, Herbarium) for 3 months improves overall satisfaction and lubrication, as well as pain, desire, sexual arousal, and ability to reach orgasm, when compared with placebo (92027,97331,97332). Other preliminary clinical research in females with HSDD shows that taking tribulus extract 7.5 mg daily for 4 weeks improves sexual desire, arousal, satisfaction, orgasm, pain, and lubrication when compared with placebo (92022). A nonblinded clinical study comparing tribulus dosing regimens shows that taking oral tribulus 280 mg, either once daily or in three divided daily doses, for 90 days results in similar improvements in sexual dysfunction, regardless of menopausal status. However, neither dosing schedule increases clitoral blood flow when compared with baseline (108551). Tribulus has also been studied in males. One clinical study in males with erectile dysfunction, with or without HSDD, shows that taking tribulus (Tribestan, Sopharma AD) 500 mg three times daily for 3 months improves sexual desire and intercourse satisfaction when compared with placebo (97330).

POSSIBLY INEFFECTIVE

• Athletic performance. Oral tribulus does not seem to improve athletic performance. Details: Small clinical studies in athletes show that taking tribulus orally, alone or in combination with other ingredients such as androstenedione, most often as 450-770 mg daily for 5-8 weeks, does not seem to enhance body composition or exercise performance when compared with placebo or a control group (7514,13255,92029,108552).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Angina. It is unclear if oral tribulus is beneficial for angina. Details: Preliminary clinical research shows that taking a tribulus extract orally might reduce symptoms of angina when compared with a control (3931).
• Atopic dermatitis (eczema). Oral tribulus has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Some preliminary clinical research shows that taking tribulus orally in combination with 9 other herbs (Zemaphyte) daily for 8 weeks reduces redness and skin lesions in adults and children with nonexudative atopic dermatitis (12627,12628). However, other research shows no effect (12630). It is unclear if these effects are due to tribulus, the other ingredients, or the combination.
• Bacterial vaginosis. Topical tribulus has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients with bacterial vaginosis shows that using a specific vaginal suppository (Forzajeh) containing tribulus, myrtle, fennel, and tamarind daily for 1 week is as effective as metronidazole vaginal suppository for improving vaginal discharge volume and odor, pelvic pain, cervical inflammation, and vaginal pH (100339). It is unclear if these effects are due to tribulus, the other ingredients, or the combination.
• Benign prostatic hyperplasia (BPH). Oral tribulus has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in adults with BPH shows that taking a combination supplement (Prostalyn, East India Pharmaceutical Works Ltd.) containing tribulus 600 mg and curry leaf (Murraya koenigii) 600 mg twice daily for 12 weeks improves prostate symptoms when compared to baseline, with no difference when compared to tamsulosin 400 mcg daily. This supplement also seems to reduce prostate volume by around 2 mL (92033).
• Cancer. Although there is interest in using oral tribulus for cancer, there is insufficient reliable information about the clinical effects of tribulus for this condition.
• Chronic fatigue syndrome (CFS). Although there is interest in using oral tribulus for CFS, there is insufficient reliable information about the clinical effects of tribulus for this condition.
• Diabetes. It is unclear if oral tribulus is beneficial for diabetes. Details: Preliminary clinical research in females with type 2 diabetes who are taking oral hypoglycemic agents shows that taking tribulus extract powder 500 mg twice daily for 3 months modestly reduces fasting glucose and postprandial glucose levels, but not glycated hemoglobin, when compared with placebo. However, the validity of these findings is limited by the difference in diabetes severity between groups at baseline (97327).
• Erectile dysfunction (ED). It is unclear if oral tribulus is beneficial for ED. Research is conflicting. Details: Clinical research in patients with ED shows that taking tribulus (Tribestan, Sopharma AD) 500 mg three times daily for 3 months does not provide a clinically beneficial improvement in erectile function when compared with placebo (97330). Other clinical research shows that taking tribulus 400 mg twice daily for 30 days does not improve erectile function when compared with placebo (92031). However, one preliminary clinical study in patients with partial androgen deficiency shows that taking tribulus 250 mg three times daily for 3 months improves erectile function when compared to baseline (92028). Tribulus has also been studied in combination with other ingredients. Preliminary clinical research shows that taking a combination supplement (Tradamix TX1000, Tradapharma Sagl) containing tribulus 450 mg, brown algae 300 mg, and chitosan 250 mg twice daily for 3 months improves sexual satisfaction, desire, ejaculation function, and sexual quality of life when compared with placebo in patients with mild-to-moderate ED (92030). It is unclear if these effects are due to tribulus, the other ingredients, or the combination.
• Exercise-induced muscle damage. It is unclear if oral tribulus is beneficial for exercise-induced muscle damage. Details: Clinical research in a small number of healthy, untrained males shows that taking tribulus 500 mg daily for 2 weeks prior to performing resistance exercise reduces markers of muscle damage, including creatine phosphokinase (CPK) and lactate dehydrogenase (LDH), but does not reduce levels of the inflammatory markers interleukin-6 (IL-6) or C-reactive protein (CRP), when compared with placebo (103236). However, another small clinical study in male CrossFit athletes shows that taking tribulus 770 mg capsules (Quamtrax Pharmaceuticals) daily for 42 days does not reduce CPK but does improve CRP and oxidant status when compared with placebo (111747). However, it is unclear whether any improvements are clinically significant. A very small crossover clinical study in trained male athletes shows that taking 20 mg/kg/day of tribulus in 3 divided doses 30 minutes before meals with 500 mL of water for 4 weeks does not reduce muscle soreness after intensive aerobic exercise when compared with placebo (111746).
• Gonorrhea. Although there is interest in using oral tribulus for gonorrhea, there is insufficient reliable information about the clinical effects of tribulus for this condition.
• Hypercholesterolemia. Although there is interest in using oral tribulus for hypercholesterolemia, there is insufficient reliable information about the clinical effects of tribulus for this condition.
• Hypertension. It is unclear if oral tribulus can lower blood pressure. Details: In patients with pre-hypertension, clinical research shows that taking powdered tribulus fruit 2 grams three times daily for 2 months reduces systolic and diastolic blood pressure by 6 and 5 mmHg, respectively, when compared with placebo (105245). It is unclear what effect Tribulus may have in patients with diagnosed hypertension.
• Kidney stones (nephrolithiasis). Although there is interest in using oral tribulus for kidney stones, there is insufficient reliable information about the clinical effects of tribulus for this purpose.
• Male infertility. It is unclear if oral tribulus is beneficial for male infertility; the available research is conflicting. Details: Case series suggest that taking a specific tribulus product (Tribestan, Sopharma) 250 mg three times daily for 30 days improves ejaculate volume, sperm concentration, and sperm motility in patients with infertility due to oligoasthenozoospermia (78865), and improves libido and erections in patients with primary hypogonadism (78868). Conversely, a small clinical study in patients with oligozoospermia shows that taking tribulus granules 6 grams daily for 60 days does not improve sperm count when compared with placebo (92032). In patients with idiopathic infertility, taking tribulus 250 mg three times daily for 3 months does not increase sperm concentration, sperm motility, serum testosterone levels, or luteinizing hormone levels (97328). The difference in these findings might be due to the small study sizes, as well as the variable etiology of infertility.
• Menopausal symptoms. Oral tribulus has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research shows that taking a combination product containing tribulus 40 mg, ginger, saffron, and Ceylon cinnamon (Aphrodit, Goldaru Company) twice daily for 4 weeks improves mental and physical symptoms during menopause, but not genitourinary symptoms, when compared with placebo (97326). It is not clear if this effect is due to tribulus, the other ingredients, or the combination.
• Osteoporosis. Although there is interest in using oral tribulus for osteoporosis, there is insufficient reliable information about the clinical effects of tribulus for this condition.
• Polycystic ovary syndrome (PCOS). Oral tribulus has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One clinical study shows that taking tribulus extract (Tribulus forte, Mediherb, Integra Healthcare Ltd) 245 mg daily along with other ingredients and lifestyle modification during the follicular phase of the menstrual cycle for 3 months improves some symptoms of PCOS, including a 33% reduction in oligomenorrhea or amenorrhea and a 43-day reduction in the duration between menstrual cycles, when compared with lifestyle modification alone. Taking tribulus with other ingredients also improves quality of life by about 30% and reduces body mass index by 1 kg/m2 when compared with placebo. Although the conception rate increased 4-fold in patients taking the combination product, the live birth rate was similar to those taking placebo. (97216). It is unclear if these effects are due to tribulus, the other ingredients, or the combination.
• Premature ejaculation. Oral tribulus has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that taking a combination product containing tribulus, 5-HTP, winter savory, and chanca piedra (EiacuMev, Farmaceutica Mev) daily for 3 months improves time to ejaculation by 30 seconds and reduces symptoms related to premature ejaculation when compared to control (97016). More evidence is needed to rate tribulus for these uses.

(Read more about TRIBULUS)

POSSIBLY EFFECTIVE

• Mastalgia. Meta-analyses of small clinical studies show that vitex agnus-castus moderately reduces breast pain due to cyclic mastalgia. Details: Two small meta-analyses of low-to-moderate quality clinical studies in patients with cyclic mastalgia show that taking vitex agnus-castus moderately reduces breast pain when compared with placebo (101981,111753). The validity of these findings is limited by the heterogeneity of the included studies. Doses of vitex agnus-castus dried fruit extract range from 3.2-40 mg daily, for 2-6 months (90617,96250,101981,111753). Vitex agnus-castus is commonly used in proprietary products, alone or in combination with other herbs (Agnucaston/Cyclodynon, Bionorica AG, Femicur, Mastodynon, Bionorica AG, Monoselect Agnus, ZE 440) (13395).
• Premenstrual syndrome (PMS). Clinical research shows that vitex agnus-castus produces modest improvements in PMS symptoms. Details: Clinical research shows that taking vitex agnus-castus fruit extract orally for 2-6 menstrual cycles seems to reduce symptoms of PMS, especially breast pain or tenderness (mastalgia), edema, constipation, irritability, depressed mood, anxiety, anger, and headache (7055,7076,7078,7079,13394,15065,41483,41489,41490,41494,90619,101981). Doses of fruit extracts have varied from 3.5-40 mg daily, usually for 2-3 menstrual cycles (7055,7076,7078,7079,15065,41483,41489,41490,90619,96435). A meta-analysis of the available clinical research, including 17 studies involving 2,401 patients, shows that taking vitex agnus-castus is comparable to fluoxetine or oral contraceptives, and modestly more effective than placebo, for reducing the symptoms of PMS. A sub-group analysis indicates that efficacy is not impacted by the dose or form used, although the dried powdered berries appear to be ineffective. The low quality of the included studies and the high level of bias and heterogeneity limit the validity of these findings (96435). Another meta-analysis limited to three randomized controlled trials shows that taking vitex agnus-castus increases the likelihood of PMS symptom remission by 2.6-fold over placebo (101979). Some clinical studies have used a specific dried extract of vitex agnus-castus fruit (Agnolyt, Madaus AG) (7076). Other studies used a specific fruit extract known as Ze 440 (Prefemin, Zeller AG), which is standardized to casticin content (7078,90619). Additional studies have used the fruit extract BNO 1095 (Agnucaston/Cyclodynon, Bionorica AG) (15065,41483,41489,41490).

POSSIBLY INEFFECTIVE

• Fractures. Limited evidence suggests that vitex agnus-castus does not improve fracture healing rates. Details: Clinical research shows that taking a specific vitex agnus-castus dried fruit extract (Agnugol, Goldaru Pharmacy Company) 4 mg, alone or in combination with magnesium oxide (Nature Made Company) 250 mg, daily for 8 weeks does not improve long bone fracture healing when compared with placebo (90618).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acne. Although there is interest in using oral vitex agnus-castus for acne, there is insufficient reliable information available about the clinical effects of vitex agnus-castus for this condition.
• Aging skin. Vitex agnus-castus has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A clinical trial in postmenopausal adults with wrinkles shows that taking one capsule orally daily of a combination of vitex agnus-castus 400 mg, evening primrose oil 500 mg, soy isoflavones 100 mg, and black cohosh 520 mg (Estosalus, Max Biocare Pty Ltd) for 12 weeks improves skin elasticity, skin smoothness, and wrinkle density scores when compared with placebo (109440).
• Amenorrhea. Although there is interest in using oral vitex agnus-castus for amenorrhea, there is insufficient reliable information available about the clinical effects of vitex agnus-castus for this condition.
• Anxiety. Although there is interest in using oral vitex agnus-castus for anxiety, there is insufficient reliable information available about the clinical effects of vitex agnus-castus for this condition.
• Benign prostatic hyperplasia (BPH). Although there is interest in using oral vitex agnus-castus for BPH, there is insufficient reliable information available about the clinical effects of vitex agnus-castus for this condition.
• Dementia. Although there is interest in using oral vitex agnus-castus for dementia, there is insufficient reliable information available about the clinical effects of vitex agnus-castus for this condition.
• Dysmenorrhea. It is unclear if oral vitex agnus-castus is beneficial in patients with dysmenorrhea. Details: Preliminary clinical research in patients with primary dysmenorrhea shows that taking a specific vitex agnus-castus extract (Agnucaston, Bionorica AG) daily for 3 months reduces pain, as measured on a visual analog scale, similarly to ethinyl estradiol 0.03 mg / drospirenone 3 mg (Yasmin) taken daily (104975).
• Fibrocystic breast disease. Although there is interest in using oral vitex agnus-castus for fibrocystic breast disease, there is insufficient reliable information available about the clinical effects of vitex agnus-castus for this condition.
• Hyperprolactinemia. Although there is interest in using oral vitex agnus-castus for hyperprolactinemia, there is insufficient reliable information available about the clinical effects of vitex agnus-castus for this condition.
• Infertility. It is unclear if oral vitex agnus-castus is beneficial for female infertility. Details: Preliminary clinical research in infertile females with oligomenorrhea or amenorrhea shows that taking homeopathic vitex agnus-castus (Phyto Hypophyson L, Steierl-Pharma GmbH) 50 drops orally three times daily for 3 months does not increase the chance of getting pregnant (41470). Also, one small clinical study in those with infertility due to secondary amenorrhea or luteal insufficiency shows that taking a vitex agnus-castus preparation (Mastodynon, Bionorica GmbH, Neumarkt/Opf.) 30 drops twice daily for at least 3 months does not increase the chance of pregnancy when compared with placebo, although the study was likely inadequately powered to detect a difference (7077).
• Insect repellent. Limited research suggests that topical vitex agnus-castus has insect repellent activity. Details: Preliminary clinical research shows that applying a carbon dioxide extract of vitex agnus-castus seeds seems to repel ticks and fleas for 6 hours, mosquitoes for 3-8 hours, and biting flies for 3 hours (13396). It is unclear how this compares with commonly used insect repellants.
• Insomnia. Although there is interest in using oral vitex agnus-castus for insomnia, there is insufficient reliable information available about the clinical effects of vitex agnus-castus for this condition.
• Lactation. Although there is interest in using oral vitex agnus-castus for stimulating lactation, there is insufficient reliable information available about the clinical effects of vitex agnus-castus for this condition.
• Menopausal symptoms. Clinical research suggests that vitex agnus-castus can relieve some menopausal symptoms; however, most research uses vitex agnus-castus in combination with other treatments. Details: Clinical research shows that taking vitex agnus-castus extract 15 mg twice daily for 8 weeks improves some menopausal symptoms, including anxiety and vasomotor dysfunction, by 76% and 88%, respectively, when compared with baseline. However, there was no effect on depression or sexual dysfunction (101980). Vitex agnus-castus has also been studied as a component of combination products. Preliminary clinical research shows that taking a combination of vitex agnus-castus, equivalent to 1000 mg dried fruit, black seed powder 500 mg, and citalopram 20 mg daily for 8 weeks reduces vasomotor, psychosocial, and physical symptoms of menopause when compared with citalopram alone (100325). Other preliminary clinical research shows that taking one capsule orally daily of a combination of vitex agnus-castus 400 mg, evening primrose oil 500 mg, soy isoflavones 100 mg, and black cohosh 520 mg (Estosalus, Max Biocare Pty Ltd) for 12 weeks moderately reduces the severity of hot flashes, sweating, sleep problems, depressed mood, and irritability when compared with placebo. There was no effect on plasma lipids, joint discomfort, anxiety, exhaustion, or sexual problems (105102). It is unclear if these effects are due to vitex agnus-castus, other ingredients, or the combination.
• Menorrhagia. It is unclear if oral vitex agnus-castus is beneficial in patients with menorrhagia. Details: A meta-analysis of two moderate quality clinical trials in patients who had heavy menstrual periods shows that taking vitex agnus-castus does not reduce menstrual bleeding over the next 1-2 menstrual cycles when compared with placebo (101982). However, preliminary clinical research in patients using an intrauterine device (IUD) shows that taking vitex agnus-castus three times daily for 8 days, starting on the first day of menstruation, and repeated for four consecutive menstrual cycles, reduces the amount of bleeding by approximately 48% when compared with baseline. This reduction was similar to the effects of mefenamic acid 250 mg daily after 4 months, although treatment with mefenamic acid was superior during the first three months (90620).
• Migraine headache. Although there is interest in using oral vitex agnus-castus for migraine headache, there is insufficient reliable information available about the clinical effects of vitex agnus-castus for this condition.
• Polycystic ovary syndrome (PCOS). Vitex agnus-castus has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in patients with oligomenorrhea due to PCOS shows that taking a traditional combination product (Aslagh) containing equivalent amounts of essential oils of vitex agnus-castus fruit, fennel, and wild carrot seeds orally daily for 3 months, either alone or in combination with metformin, improves rates of menstrual bleeding and menstrual cyclicity similarly to metformin alone. All three groups experienced a significant improvement from baseline. Aslagh was taken as two, 500-mg capsules twice daily, except during menses; metformin was titrated over one week to a dose of 500 mg three times daily (108974).
• Premenstrual dysphoric disorder (PMDD). Limited evidence suggests that vitex agnus-castus might improve symptoms of PMDD. Details: In a clinical trial, vitex agnus-castus 20-40 mg daily for 8 weeks was similar to fluoxetine 20-40 mg daily for relieving symptoms of PMDD. About 58% of patients responded to vitex agnus-castus, compared to about 68% of patients taking fluoxetine. Vitex agnus-castus was more effective for physical symptoms such as breast tenderness, swelling, cramps, and food cravings (12207,41493).
• Rheumatoid arthritis (RA). Although there is interest in using oral vitex agnus-castus for RA, there is insufficient reliable information available about the clinical effects of vitex agnus-castus for this condition.
• Sexual dysfunction. It is unclear if oral vitex agnus-castus is beneficial in patients with sexual dysfunction. Details: Preliminary clinical research in healthy females under 44 years of age with sexual dissatisfaction shows that taking a specific vitex agnus-castus product (Agnugol, Goldaru Herbal Pharmaceutical Company) 3.2-4.8 mg orally once daily for 16 weeks modestly improves scores of sexual satisfaction, function, arousal, and desire when compared with placebo (109437). Additionally, a moderate-sized clinical study in females 50-69 years old with sexual dysfunction conducted in Iran shows that taking vitex agnus-castus 40 drops daily for 8 weeks improves sexual dysfunction scores from mild dysfunction to no dysfunction at 6 and 8 weeks when compared with placebo but does not improve scores at 4 weeks (112361). More evidence is needed to rate the effectiveness of vitex agnus-castus for these uses.

(Read more about VITEX AGNUS-CASTUS)

POSSIBLY INEFFECTIVE

• Menopausal symptoms. Topical wild yam does not seem to improve menopausal symptoms. Details: Wild yam applied topically as a cream in menopausal patients for 3 months appears to be no better than placebo for relieving vasomotor symptoms, such as hot flashes and night sweats. It also does not appear to change serum follicle stimulating hormone (FSH), estradiol, or progesterone levels (10989).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Cognitive function. It is unclear if oral wild yam is beneficial for improving cognitive function in healthy adults. Details: Preliminary clinical research in healthy adults shows that taking a specific wild yam extract (Diopower 15, Anti-Aging Pro Corporation) orally, 50 mg (containing diosgenin 8 mg) daily for 12 weeks, modestly improves overall measures of cognitive function and semantic fluency when compared with placebo (96724).
• Dysmenorrhea. Although there is interest in using oral or topical wild yam for dysmenorrhea, there is insufficient reliable information about the clinical effects of wild yam for this condition.
• Gallbladder disease. Although there is interest in using oral wild yam for gallbladder disease, there is insufficient reliable information about the clinical effects of wild yam for this condition.
• Infertility. Although there is interest in using oral or topical wild yam for infertility, there is insufficient reliable information about the clinical effects of wild yam for this condition.
• Osteoporosis. Although there is interest in using oral wild yam for osteoporosis, there is insufficient reliable information about the clinical effects of wild yam for this condition.
• Postmenopausal conditions. Although there is interest in using oral wild yam for postmenopausal conditions, there is insufficient reliable information about the clinical effects of wild yam for these conditions.
• Premenstrual syndrome (PMS). Although there is interest in using oral wild yam for PMS, there is insufficient reliable information about the clinical effects of wild yam for this condition.
• Rheumatoid arthritis (RA). Although there is interest in using oral wild yam for RA, there is insufficient reliable information about the clinical effects of wild yam for this condition.
• Sexual dysfunction. Although there is interest in using oral wild yam for sexual dysfunction, there is insufficient reliable information about the clinical effects of wild yam for this condition. More evidence is needed to rate wild yam for these uses.

(Read more about WILD YAM)

LIKELY SAFE ...when used orally in amounts commonly found in foods. Black pepper has Generally Recognized as Safe (GRAS) status in the US (4912).

POSSIBLY SAFE ...when black pepper oil is applied topically. Black pepper oil is nonirritating to the skin and is generally well tolerated (11). ...when black pepper oil is inhaled through the nose or as a vapor through the mouth, short-term. Black pepper oil as a vapor or as an olfactory stimulant has been used with apparent safety in clinical studies for up to 3 days and 30 days, respectively (29159,29160,29161,90502). There is insufficient reliable information available about the safety of black pepper when used orally in medicinal amounts.

CHILDREN: LIKELY SAFE
when used orally in amounts commonly found in foods (11).

CHILDREN: POSSIBLY UNSAFE
when used orally in large amounts. Fatal cases of pepper aspiration have been reported in some patients (5619,5620). There is insufficient reliable information available about the safety of topical pepper oil when used in children.

PREGNANCY: LIKELY SAFE
when used orally in amounts commonly found in foods (11).

PREGNANCY: LIKELY UNSAFE
when used orally in large amounts. Black pepper might have abortifacient effects (11,19); contraindicated. There is insufficient reliable information available about the safety of topical pepper when used during pregnancy.

LACTATION: LIKELY SAFE
when used orally in amounts commonly found in foods (11). There is insufficient reliable information available about the safety of black pepper when used in medicinal amounts during breast-feeding.

(Read more about BLACK PEPPER)

LIKELY SAFE ...when used orally in amounts commonly found in foods. Damiana has Generally Recognized As Safe status (GRAS) for use in foods in the US (4912).

POSSIBLY SAFE ...when used orally and appropriately in medicinal amounts (12,46933,11866).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

(Read more about DAMIANA)

POSSIBLY SAFE ...when used orally and appropriately. Dong quai has been used with apparent safety in a dose of 4.5 grams daily for 24 weeks, or in combination with other ingredients in doses of up to 150 mg daily for up to 6 months (19552,35797). ...when used intravenously as a 25% solution, in a dose of 200-250 mL daily for up to 20 days (48438,48442,48443,48483).

POSSIBLY UNSAFE ...when used orally in large amounts, long-term. Theoretically, long-term use of large amounts of dong quai could be harmful. Dong quai contains several constituents such as bergapten, safrole, and isosafrole that are considered carcinogenic (7162). There is insufficient reliable information available about the safety of dong quai when used topically.

PREGNANCY: POSSIBLY UNSAFE
when used orally. Dong quai has uterine stimulant and relaxant effects (8142); theoretically, it could adversely affect pregnancy. Observational research has found that intake of An-Tai-Yin, an herbal combination product containing dong quai and parsley, during the first trimester is associated with an increased risk of congenital malformations of the musculoskeletal system, connective tissue, and eyes (15129).

LACTATION:
Insufficient reliable information available; avoid use.

(Read more about DONG QUAI)

POSSIBLY SAFE ...when used orally, short-term. Kava extracts have been used safely in clinical trials under medical supervision for up to 6 months (2093,2094,2095,4032,7325,15046,15130,18314,18316,18318)(18320,29663,29671,98980,102086,112642). Historically, there has been some concern that kava preparations could induce hepatotoxicity and liver failure in patients taking relatively normal doses, short-term. At least 100 cases of liver toxicity following kava use have been reported. Although liver toxicity is more frequently associated with prolonged use of very high doses (6401,57346), in some cases the use of kava for as little as 1-3 months has been associated with the need for liver transplants, and even death (390,7024,7068,7086,7096,17086,57252)(57254,57297). However, some experts question the clinical validity of several of these cases (11369,11371).

PREGNANCY: POSSIBLY UNSAFE
when used orally. There is some concern that pyrone constituents in kava can cause loss of uterine tone (19); avoid using.

LACTATION: POSSIBLY UNSAFE
when used orally. There is concern that the toxic pyrone constituents of kava can pass into breast milk (19); avoid using.

(Read more about KAVA)

LIKELY SAFE ...when maca is consumed in food amounts (9926).

POSSIBLY SAFE ...when used orally and appropriately, short term. Maca appears to be safe in doses up to 3 grams daily for 4 months (9928,10218,18289,90278,108603).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

(Read more about MACA)

POSSIBLY SAFE ...when used orally and appropriately, short-term. Taking muira puama 500-1050 mg daily, as part of a combination product, has been used with apparent safety for 1 month (63920,103224). There is insufficient reliable information available about the safety of muira puama when used long-term.

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

(Read more about MUIRA PUAMA)

LIKELY SAFE ...when niacin is taken in food or as a supplement in amounts below the tolerable upper intake level (UL) of 30 mg daily for adults 18 years of age and 35 mg daily for adults 19 years and older (6243). ...when prescription products are used orally and appropriately in doses of up to 2 grams daily (12033). CHILDREN:

LIKELY SAFE ...when used orally in amounts that do not exceed the tolerable upper intake level (UL). The ULs of niacin for children are: 1-3 years of age, 10 mg daily; 4-8 years of age, 15 mg daily; 9-13 years of age, 20 mg daily; 14-18 years of age, 30 mg daily (6243).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally in amounts that do not exceed the tolerable upper intake level (UL). The UL of niacin during pregnancy and lactation is 30 mg daily for 14-18 years of age and 35 mg daily for 19 years and older (6243). There is insufficient reliable information available about the safety of larger oral doses of niacin during pregnancy or lactation; avoid using.

(Read more about NIACIN)

LIKELY SAFE ...when used orally and appropriately in food amounts (4960,4969,5792,5797). Oat bran has Generally Recognized as Safe (GRAS) status in the US (4912). Whole grain oats 50-100 grams daily have been used for up to 1 year without serious adverse effects (97520).

POSSIBLY SAFE ...when used topically and appropriately (12). Lotion containing colloidal oat 1% has been used topically without adverse effects for up to 6 weeks (97518,103340). There is insufficient reliable information available about the safety of oats when used orally in medicinal amounts.

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally in food amounts (5792,5797).

(Read more about OATS)

LIKELY SAFE ...when used orally and appropriately. St. John's wort extracts in doses up to 900 mg daily seem to be safe when used for up to 12 weeks (3547,3550,4835,5096,6400,6434,7047,13021,13156,13157)(14417,76143,76144,89666,89669,95510). Some evidence also shows that St. John's wort can be safely used for over one year (13156,13157,76140), and may have better tolerability than selective serotonin reuptake inhibitors (SSRIs) and tricyclic antidepressants (TCAs) (4897,76153,76143,104036).

POSSIBLY SAFE ...when used topically and appropriately. St. John's wort 0.5% extract seems to be safe when used once weekly for 4 weeks (110327). St. John's wort oil has been used with apparent safely twice daily for 6 weeks (110326). However, topical use of St. John's wort can cause photodermatitis with sun exposure (110318).

POSSIBLY UNSAFE ...when used orally in large doses. St. John's wort extract can be unsafe due to the risk of severe phototoxic skin reactions. Taking 2-4 grams of St. John's wort extract (containing hypericin 5-10 mg) daily appears to increase the risk of photosensitivity (758,4631,7808).

PREGNANCY: POSSIBLY UNSAFE
when used orally. Preliminary population research has found that taking St. John's wort while pregnant is associated with offspring that develop neural tube, urinary, and cardiovascular malformations. Subgroup analyses suggest that these risks may be higher when taking St. John's wort during the first trimester when compared with the second or third trimester. However, more research is needed to confirm these findings (106052). Animal-model research also shows that constituents of St. John's wort might have teratogenic effects (9687,15122). Until more is known, St. John's wort should not be taken during pregnancy.

LACTATION: POSSIBLY UNSAFE
when used orally. Nursing infants of mothers who take St. John's wort have a greater chance of experiencing colic, drowsiness, and lethargy (1377,15122,22418); avoid using.

CHILDREN: POSSIBLY SAFE
when used orally, and appropriately, short-term. St. John's wort extracts in doses up to 300 mg three times daily seem to be safe when used for up to 8 weeks in children aged 6-17 years (4538,17986,76110).

(Read more about ST. JOHN'S WORT)

LIKELY UNSAFE ...when the spine-covered fruit is used orally. There have been reports of bilateral pneumothorax and bronchial polyp after oral consumption of the spine-covered fruit (818).

PREGNANCY: POSSIBLY UNSAFE
when used orally. Animal research suggests that tribulus might adversely affect fetal development (12674); avoid using.

LACTATION:
Insufficient reliable information available; avoid using.

(Read more about TRIBULUS)

LIKELY SAFE ...when the fruit extract is used orally and appropriately, short-term. Vitex agnus-castus fruit extract has been used safely in studies at doses up to 40 mg daily, for up to 3 months (7055,7076,7077,7078,7079,12207,13393,15065,90617,90618,96435). There is insufficient reliable information available about the safety of vitex agnus-castus seeds when used orally or topically.

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally. Theoretically, the hormonal effects of vitex agnus-castus might adversely affect pregnancy or lactation (10979,11456,13393,109439). Animal research shows that taking vitex agnus-castus fruit extract when planning to become pregnant or during pregnancy may increase the risk of infertility, low fetal body weight, abortion, and stillbirth (109439); avoid using.

(Read more about VITEX AGNUS-CASTUS)

POSSIBLY SAFE ...when used orally. A dose of 50 mg (containing 8 mg diosgenin) has been used with apparent safety for 12 weeks (12,96724). ...when used topically. A wild yam cream has been used with apparent safety for 3 months (10989).

PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.

(Read more about WILD YAM)

AMOXICILLIN (Amoxil, Trimox) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, black pepper might increase the effects and side effects of amoxicillin.  Details Animal research shows that taking piperine, a constituent of black pepper, with amoxicillin increases plasma levels of amoxicillin (29269). This has not been reported in humans.

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, black pepper might increase the risk of bleeding when taken with antiplatelet or anticoagulant drugs.  Details In vitro research shows that piperine, a constituent of black pepper, seems to inhibit platelet aggregation (29206). This has not been reported in humans.

ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, black pepper might increase the risk of hypoglycemia when taken with antidiabetes drugs.  Details Animal research shows that piperine, a constituent of black pepper, can reduce blood glucose levels (29225). Monitor blood glucose levels closely. Dose adjustments might be necessary.

ATORVASTATIN (Lipitor) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, black pepper might increase blood levels of atorvastatin.  Details Animal research shows that taking piperine, a constituent of black pepper, 35 mg/kg can increase the maximum serum concentration of atorvastatin three-fold (104188). This has not been reported in humans.

CARBAMAZEPINE (Tegretol) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Theoretically, black pepper might increase blood levels of carbamazepine, potentially increasing the effects and side effects of carbamazepine.  Details One clinical study in patients taking carbamazepine 300 mg or 500 mg twice daily shows that taking a single 20 mg dose of purified piperine, a constituent of black pepper, increases carbamazepine levels. Piperine may increase carbamazepine absorption by increasing blood flow to the GI tract, increasing the surface area of the small intestine, or inhibiting cytochrome P450 3A4 (CYP3A4) in the gut wall. Absorption was significantly increased by 7-10 mcg/mL/hour. The time to eliminate carbamazepine was also increased by 4-8 hours. Although carbamazepine levels were increased, this did not appear to increase side effects (16833). In vitro research also shows that piperine can increase carbamazepine levels by 11% in a time-dependent manner (103819).

CYCLOSPORINE (Neoral, Sandimmune) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, black pepper might increase the effects and side effects of cyclosporine.  Details In vitro research shows that piperine, a constituent of black pepper, increases the bioavailability of cyclosporine (29282). This has not been reported in humans.

CYTOCHROME P450 1A1 (CYP1A1) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, black pepper might increase levels of drugs metabolized by CYP1A1.  Details In vitro research suggests that piperine, a constituent of black pepper, inhibits CYP1A1 (29213). This has not been reported in humans.

CYTOCHROME P450 2B1 (CYP2B1) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, black pepper might increase levels of drugs metabolized by CYP2B1.  Details In vitro research suggests that piperine, a constituent of black pepper, inhibits CYP2B1 (29332). This has not been reported in humans.

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, black pepper might increase levels of drugs metabolized by CYP2D6.  Details In vitro research suggests that some constituents of black pepper inhibit CYP2D6 (29207,29212,38375). This has not been reported in humans.

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, black pepper might increase levels of drugs metabolized by CYP3A4.  Details In vitro research shows that piperine, a constituent of black pepper, as well as the pepper fruit seem to inhibit CYP3A4 (14375,29212). This has not been reported in humans.

LITHIUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, black pepper might increase blood levels of lithium due to its diuretic effects. The dose of lithium might need to be reduced.  Details Black pepper is thought to have diuretic properties (11).

NEVIRAPINE (Viramune) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = D Black pepper might increase blood levels of nevirapine.  Details Clinical research shows that piperine, a constituent of black pepper, increases the plasma concentration of nevirapine. However, no adverse effects were observed in this study (29209).

P-GLYCOPROTEIN SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, black pepper might increase levels of P-glycoprotein substrates.  Details In vitro research shows that piperine, a constituent of black pepper, seems to inhibit P-glycoprotein (14375,29281,29283).

PENTOBARBITAL (Nembutal) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, black pepper might increase the sedative effects of pentobarbital.  Details Animal research shows that piperine, a constituent of black pepper, increases pentobarbital-induced sleeping time (29214).

PHENYTOIN (Dilantin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Black pepper might increase blood levels of phenytoin.  Details Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption, slow elimination, and increase levels of phenytoin (537,14442). Taking a single dose of black pepper 1 gram along with phenytoin seems to double the serum concentration of phenytoin (14375). Consuming a soup with black pepper providing piperine 44 mg/200 mL of soup along with phenytoin also seems to increase phenytoin levels when compared with consuming the same soup without black pepper (14442).

PROPRANOLOL (Inderal) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Black pepper might increase blood levels of propranolol.  Details Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption and slow elimination of propranolol (538).

RIFAMPIN (Rifadin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Black pepper might increase blood levels of rifampin.  Details Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption and serum levels of rifampin (14375,29284).

THEOPHYLLINE Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Black pepper might increase blood levels of theophylline.  Details Clinical research shows that piperine, a constituent of black pepper, seems to increase absorption and slow elimination of theophylline (538).

(Read more about BLACK PEPPER)

ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking damiana with antidiabetes drugs might increase the risk of hypoglycemia.  Details Animal research shows that taking damiana lowers blood glucose level (4,25016).

(Read more about DAMIANA)

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, dong quai may increase the risk of bleeding when used with anticoagulant or antiplatelet drugs; however, research is conflicting.  Details Animal studies suggest that dong quai has antithrombin activity and inhibits platelet aggregation due to its coumarin components (6048,10057,96137). Additionally, some case reports in humans suggest that dong quai can increase the anticoagulant effects of warfarin (3526,6048,23310,48439). However, clinical research in healthy adults shows that taking 1 gram of dong quai root daily for 3 weeks does not significantly inhibit platelet aggregation or cause bleeding (96137). Until more is known, use dong quai with caution in patients taking antiplatelet/anticoagulant drugs.

ESTROGENS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, dong quai may reduce the effects of estrogens.  Details Dong quai has estrogenic effects (6180,7860,15108,15535,48459). Theoretically, concomitant use of large amounts of dong quai might interfere with hormone replacement therapy due to competition for estrogen receptors.

WARFARIN (Coumadin) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = D Dong quai may increase the risk of bleeding when used with warfarin.  Details Case reports suggest that concomitant use of dong quai with warfarin can increase the anticoagulant effects of warfarin and increase the risk of bleeding (3526,6048,23310,48439). In one case, after 4 weeks of taking dong quai 565 mg once or twice daily, the international normalized ratio (INR) increased to 4.9. The INR normalized 4 weeks after discontinuation of dong quai (3526).

(Read more about DONG QUAI)

ALCOHOL (ETHANOL) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = A Combining kava with alcohol may increase the risk of sedation and/or hepatotoxicity.  Details Kava has CNS depressant effects (11373,18316). Concomitant use of kava with other CNS depressants can increase the risk of drowsiness and motor reflex depression (2093,2098). Additionally, kava has been associated with over 100 cases of hepatotoxicity. There is some concern that kava can adversely affect the liver, especially when used in combination with hepatotoxic drugs (7024,7068,7086,7096,17086,57346). Clinical practice guidelines from a joint taskforce of the World Federation of Societies of Biological Psychiatry (WFSBP) and the Canadian Network for Mood and Anxiety Treatments (CANMAT) recommend that alcohol not be used with kava (110318).

CNS DEPRESSANTS Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = A Combining kava with CNS depressants can have additive sedative effects.  Details Kava has CNS depressant effects (11373,18316). Concomitant use of kava with other CNS depressants can increase the risk of drowsiness and motor reflex depression (2093,2098). Clinical practice guidelines from a joint taskforce of the World Federation of Societies of Biological Psychiatry (WFSBP) and the Canadian Network for Mood and Anxiety Treatments (CANMAT) recommend that CNS depressants, including alcohol and benzodiazepines, not be used with kava (110318).

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = B It is unclear if kava inhibits CYP1A2; research is conflicting.  Details Although in vitro research and a case report suggest that kava inhibits CYP1A2 (8743,12479,88593), more robust clinical evidence shows that kava has no effect on CYP1A2. In a clinical study in healthy volunteers, taking kava 1000 mg twice daily (containing a daily dose of 138 mg kavalactones) for 28 days had no effect on CYP1A2 activity (13536,98979).

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, kava might increase levels of CYP2C19 substrates.  Details In vitro research shows that kava significantly inhibits CYP2C19 enzymes (8743,12479). This effect has not yet been reported in humans.

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, kava might increase levels of CYP2C9 substrates.  Details In vitro research shows that kava significantly inhibits CYP2C9 enzymes (8743,12479). This effect has not yet been reported in humans.

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = B It is unclear if kava inhibits CYP1A2; research is conflicting.  Details In vitro research shows that kava extract significantly inhibits CYP2D6 (8743,12479). However, clinical research shows that kava does not affect the metabolism of CYP2D6 substrates in humans (13536,16848,98979).

CYTOCHROME P450 2E1 (CYP2E1) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Kava might increase levels of CYP2E1 substrates.  Details In a clinical study in healthy volunteers, taking kava 1000 mg twice daily (containing a daily dose of 138 mg kavalactones) for 28 days inhibited the metabolism of CYP2E1 substrates (13536).

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = B It is unclear if kava inhibits CYP3AA; research is conflicting.  Details Although in vitro research suggests that kava inhibits CYP3A4 (8743,12479), more robust clinical evidence shows that kava has no effect on CYP3A4. In a clinical study in healthy volunteers, taking kava 1000 mg twice daily (containing a daily dose of 138 mg kavalactones) for 28 days had no effect on CYP3A4 activity (13536,98979).

HALOPERIDOL (Haldol) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Combining kava and haloperidol might increase the risk of cardiovascular adverse effects and hypoxia.  Details Atrial flutter and hypoxia has been reported for a patient who received intramuscular injections of haloperidol and lorazepam after using kava orally. The side effects were attributed to kava-induced inhibition of CYP2D6, but might also have been related to additive adverse effects with the concomitant use of haloperidol, lorazepam, and kava (88593).

HEPATOTOXIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, using kava with hepatotoxic drugs might increase the risk of liver damage.  Details Kava has been linked with over 100 cases of hepatotoxicity. Most cases occur with excessive and prolonged use. There is some concern that kava can adversely affect the liver, especially when used in combination with hepatotoxic drugs (7024,7068,7086,7096,17086,57346).

P-GLYCOPROTEIN SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D It is unclear if kava inhibits P-glycoprotein (P-gp); research is conflicting.  Details In vitro research shows that kava can inhibit P-gp efflux (15131). However, a clinical study in healthy volunteers shows that taking kava standardized to provide 225 mg kavalactones daily for 14 days does not affect the pharmacokinetics of digoxin, a P-gp substrate (15132,98979). It is possible that the use of other P-gp substrates or higher doses of kava might still inhibit P-gp.

ROPINIROLE (Requip) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Taking kava with ropinirole might increase the risk for dopaminergic toxicity.  Details A case of visual hallucinations and paranoid delusions has been reported for a patient who used kava in combination with ropinirole. The adverse effects were attributed to kava-induced inhibition of CYP1A2, which may have reduced the metabolism of ropinirole, resulting in excessive dopaminergic stimulation (88593).

(Read more about KAVA)

(Read more about MACA)

(Read more about MUIRA PUAMA)

ALCOHOL (Ethanol) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Concomitant use of alcohol and niacin might increase the risk of flushing and hepatotoxicity.  Details Alcohol can exacerbate the flushing and pruritus associated with niacin (4458,11689). Large doses of niacin might also exacerbate liver dysfunction associated with chronic alcohol use. A case report describes delirium and lactic acidosis in a patient taking niacin 3 grams daily who ingested 1 liter of wine (14510). Advise patients to avoid large amounts of alcohol while taking niacin.

ALLOPURINOL (Zyloprim) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Theoretically, niacin might antagonize the therapeutic effects of uricosurics such as allopurinol.  Details Large doses of niacin can reduce urinary excretion of uric acid, potentially resulting in hyperuricemia (4860,4863,12033). Doses of uricosurics such as allopurinol might need to be increased to maintain control of gout in patients who start taking niacin (4458). People who have frequent attacks of gout despite uricosuric therapy should avoid niacin (4863).

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, niacin may have additive effects when used with anticoagulant or antiplatelet drugs.  Details Several cases of clotting factor synthesis deficiency and coagulopathy have been reported in patients taking sustained-release niacin (25915). Also, thrombocytopenia has been reported in patients treated with niacin or niacin plus lovastatin (25916).

ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Niacin can increase blood glucose levels and may diminish the effects of antidiabetes drugs.  Details Niacin impairs glucose tolerance in a dose-dependent manner, probably by causing or aggravating insulin resistance and increasing hepatic production of glucose (4860,4863,11692,11693). In diabetes patients, niacin 4.5 grams daily for 5 weeks can increase plasma glucose by an average of 16% and glycated hemoglobin (HbA1c) by 21% (4860). However, lower doses of 1.5 grams daily or less appear to have minimal effects on blood glucose (12033). In some patients, glucose levels increase when niacin is started, but then return to baseline when a stable dose is reached (12033,93344). Up to 35% of patients with diabetes may need adjustments in hypoglycemic therapy when niacin is added (4458,4860,4863,11689,12033).

ANTIHYPERTENSIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, niacin may increase the risk of hypotension when used with antihypertensive drugs.  Details The vasodilating effects of niacin can cause hypotension (4863,12033,93341). Furthermore, some clinical evidence suggests that a one-hour infusion of niacin can reduce systolic, diastolic, and mean blood pressure in hypertensive patients. This effect is not observed in normotensive patients (25917).

ASPIRIN Interaction Rating = Minor Be watchful with this combination. Severity = Insignificant •  Occurrence = Likely •  Level of Evidence = B Large doses of aspirin might alter the clearance of niacin.  Details Aspirin is often used with niacin to reduce niacin-induced flushing (4458,11689). Doses of 80-975 mg aspirin have been used, but 325 mg appears to be optimal (4458,4852,4853,11689). Aspirin also seems to reduce the clearance of niacin by competing for glycine conjugation. Taking aspirin 1 gram seems to reduce niacin clearance by 45% (14524). This is probably a dose-related effect and not clinically significant with the more common aspirin dose of 325 mg (11689,14524).

BILE ACID SEQUESTRANTS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Bile acid sequestrants can bind niacin and decrease absorption. Separate administration by 4-6 hours to avoid an interaction.  Details In vitro studies show that colestipol (Colestid) binds about 98% of available niacin and cholestyramine (Questran) binds 10% to 30% (14511).

GEMFIBROZIL (Lopid) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of niacin and gemfibrozil might increase the risk of myopathy in some patients.  Details A case of myopathy from concomitant use of niacin and gemfibrozil has been reported (25920). Niacin alone has also been associated with cases of myopathy (26100,26111). Using gemfibrozil with niacin might further increase the risk of developing myopathy.

HEPATOTOXIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of niacin and hepatotoxic drugs might increase the risk of hepatotoxicity.  Details Niacin has been associated with cases of liver toxicity, especially when used in pharmacologic doses (4863,11689,11691,25929,25930,25931,113553). Sustained-release niacin preparations appear to be associated with a higher risk of hepatotoxicity than immediate-release niacin (11691,25930,25931,93342,113553).

HMG-CoA REDUCTASE INHIBITORS ("Statins") Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of niacin and statins might increase the risk of myopathy and rhabdomyolysis in some patients.  Details Some case reports have raised concerns that niacin might increase the risk of myopathy and rhabdomyolysis when combined with statins (14508,25918). However, a significantly increased risk of myopathy has not been demonstrated in clinical trials, including those using an FDA-approved combination of lovastatin and niacin (Advicor) (7388,11689,12033,14509).

PROBENECID (Benemid) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Theoretically, niacin might antagonize the therapeutic effects of uricosurics such as probenecid.  Details Large doses of niacin reduce urinary excretion of uric acid, potentially causing hyperuricemia (4863,12033). Doses of uricosurics such as probenecid might need to be increased to maintain control of gout in patients who start taking niacin (4458). People who have frequent attacks of gout despite uricosuric therapy should avoid niacin (4863).

SULFINPYRAZONE (Anturane) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Theoretically, niacin might antagonize the therapeutic effects of uricosurics such as sulfinpyrazone.  Details Large doses of niacin reduce urinary excretion of uric acid, potentially causing hyperuricemia (4863,12033). Doses of uricosurics such as sulfinpyrazone might need to be increased to maintain control of gout in patients who start taking niacin (4458). People who have frequent attacks of gout despite uricosuric therapy should avoid niacin (4863).

THYROID HORMONE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, niacin might antagonize the therapeutic effects of thyroid hormones.  Details Clinical research and case reports suggests that taking niacin can reduce serum levels of thyroxine-binding globulin by up to 25% and moderately reduce levels of thyroxine (T4) (25916,25925,25926,25928). Patients taking thyroid hormone for hypothyroidism might need dose adjustments when using niacin.

TRANSDERMAL NICOTINE (Nicoderm) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of niacin and transdermal nicotine might increase the risk of flushing and dizziness.  Details Niacin and nicotine can both cause flushing and dizziness (496,96211).

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ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, oats may have additive effects with antidiabetic agents and might increase the risk of hypoglycemia.  Details Consuming oats can decrease blood glucose in patients with diabetes (4980,4982,6266,103345). In those who require insulin, taking oats 100 grams daily for 2 days reduces the insulin dose required to achieve metabolic control (103336).

INSULIN Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Concomitant use of oats and insulin might increase the risk of hypoglycemia.  Details In patients with insulin-dependent type 2 diabetes, taking oats 100 grams daily for 2 days reduces the insulin dose required to achieve metabolic control (103336).

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ALPRAZOLAM (Xanax) Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B St. John's wort increases the clearance of alprazolam and decreases its effects.  Details Alprazolam, which is used as a probe for cytochrome P450 3A4 (CYP3A4) activity, has a two-fold increase in clearance when given with St. John's wort. St. John's wort reduces the half-life of alprazolam from 12.4 hours to 6 hours (10830).

AMBRISENTAN (Letairis) Interaction Rating = Minor Be watchful with this combination. Severity = Insignificant •  Occurrence = Probable •  Level of Evidence = B St. John's wort may increase the clearance of ambristentan and decrease its effects.  Details Clinical research in healthy volunteers shows that taking St. John's wort 900 mg daily decreases the area under the concentration-time curve of ambrisentan 5 mg by 17% to 26%. Ambrisentan clearance was increased by 20% to 35% depending on CYP2C19 genotype. However, these small changes are unlikely to be clinically significant (99511).

AMINOLEVULINIC ACID Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D St. John's wort might have additive phototoxic effects with aminolevulinic acid.  Details Concomitant use with St. John's wort extract may cause synergistic phototoxicity. Delta-aminolevulinic acid can cause a burning erythematous rash and severe swelling of the face, neck, and hands when taken with St. John's wort (9474).

BOCEPREVIR (Victrelis) Interaction Rating = Minor Be watchful with this combination. Severity = Insignificant •  Occurrence = Possible •  Level of Evidence = B St. John's wort might decrease the levels and clinical effects of boceprevir.  Details Boceprevir increases the maximum concentration and concentration at 8 hours of the St. John's wort constituent, hypericin, by approximately 30%. However, St. John's wort does not significantly change the area under the concentration-time curve or maximum plasma concentration of boceprevir 800 mg three times daily in healthy adults (95507,96552).

BUPROPION (Wellbutrin) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B St. John's wort might reduce the levels and effects of bupropion.  Details Clinical research shows that taking St. John's wort 325 mg three times daily for 14 days along with bupropion reduces the area under the concentration-time curve by approximately 14% and increases the clearance of bupropion by approximately 20%. This effect is attributed to the induction of cytochrome P450 2B6 (CYP2B6) by St. John's wort (89662).

CLOPIDOGREL (Plavix) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B St. John's wort might increase the levels and effects of clopidogrel.  Details Taking St. John's wort with clopidogrel seems to increase the activity of clopidogrel. In clopidogrel non-responders, taking St. John's wort seems to induce metabolism of clopidogrel to its active metabolite by cytochrome P450 enzymes 3A4 and 2C19. This leads to increased antiplatelet activity (13038,89671,96552). Theoretically, this might lead to an increased risk of bleeding in clopidogrel responders.

CLOZAPINE (Clozaril) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D St. John's wort might decrease the levels and clinical effects of clozapine.  Details A case report describes a female with schizophrenia controlled on clozapine who had a return of symptoms when she started taking St. John's wort. The plasma concentration of clozapine was reduced, likely because its clearance was increased due to induction of the cytochrome P450 enzymes 3A4, 1A2, 2C9, and 2C19 by St. John's wort (96552).

CONTRACEPTIVE DRUGS Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B St. John's wort increases the clearance of contraceptive drugs and reduces their clinical effects.  Details Females taking St. John's wort and oral contraceptives concurrently should use an additional or alternative form of birth control. St. John's wort can decrease norethindrone and ethinyl estradiol levels by 13% to 15%, resulting in breakthrough bleeding, irregular menstrual bleeding, or unplanned pregnancy (11886,11887,13099). Bleeding irregularities usually occur within a week of starting St. John's wort and regular cycles usually return when St. John's wort is discontinued. Unplanned pregnancy has occurred with concurrent use of oral contraceptives and St. John's wort extract (9880). St. John's wort is thought to induce the cytochrome P450 1A2 (CYP1A2), 2C9 (CYP2C9), and 3A4 (CYP3A4) enzymes, which are responsible for metabolism of progestins and estrogens in contraceptives (1292,7809,9204).

CYCLOSPORINE (Neoral, Sandimmune) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B St. John's wort reduces the levels and clinical effects of cyclosporine.  Details Concomitant use can decrease plasma cyclosporine levels by 30% to 70% (1234,4826,4831,4834,7808,9596,10628,96552). Using St. John's wort with cyclosporine in patients with heart, kidney, or liver transplants can cause subtherapeutic cyclosporine levels and acute transplant rejection (1234,1293,1301,6112,6435,7808,9596). This interaction has occurred with a St. John's wort extract standardized to 0.3% hypericin and dosed at 300-600 mg per day (6435,10628). Withdrawal of St. John's wort can result in a 64% increase in cyclosporine levels (1234,4513,4826,4831,4834). St. John's wort induces cytochrome P450 3A4 (CYP3A4) and the multi-drug transporter, P-glycoprotein/MDR-1, which increases cyclosporine clearance (1293,1340,9204,9596).

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B St. John's wort may increase the metabolism and reduce the levels of CYP1A2 substrates.  Details Clinical and in vitro research shows that St. John's wort induces CYP1A2, but to a lesser extent than CYP3A4 (9204,10848,76163,111404).

CYTOCHROME P450 2B6 (CYP2B6) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B St. John's wort may increase the metabolism and reduce the levels of CYP2B6 substrates.  Details Clinical research shows that taking St. John's wort 325 mg three times daily for 14 days along with bupropion, a CYP2B6 substrate, reduces the area under the concentration-time curve by approximately 14% and increases the clearance of bupropion by approximately 20% (89662).

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B St. John's wort may increase the metabolism and reduce the levels of CYP2C19 substrates.  Details Preliminary clinical research in healthy males shows that taking St. John's wort for 14 days induces CYP2C19 and increases metabolism of mephenytoin (Mesantoin). In patients with wild-type 2C19 (2C19*1/*1) metabolism was almost 4-fold greater in subjects who received St. John's wort compared to placebo. In contrast, patients with 2C19*2/*2 and *2/*3 genotypes did not demonstrate a similar increase in metabolism (17405). Theoretically, St. John's wort might increase metabolism of other CYP2C19 substrates.

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B St. John's wort may increase the metabolism and reduce the levels of CYP2C9 substrates.  Details There is contradictory research about the effect of St. John's wort on CYP2C9. Some in vitro research shows that St. John's wort induces CYP2C9, but to a lesser extent than CYP3A4 (9204,10848,11889). St. John's wort also induces metabolism of the S-warfarin isomer, which is a CYP2C9 substrate (11890). Other research shows that St. John's wort 300 mg three times daily for 21 days does not significantly affect the pharmacokinetics of a single 400 mg dose of ibuprofen, which is also a CYP2C9 substrate (15546). Until more is known, use St. John's wort cautiously in patients who are taking CYP2C9 substrates.

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B St. John's wort increases the metabolism and reduces the levels of CYP3A4 substrates.  Details St. John's wort induces CYP3A4 enzymes and increases metabolism of CYP3A4 substrates (9204,10830,10847,10848,11889,22423,22424,22425,22427,48603,111404,111644,113094). Clinically significant interactions have been reported with St. John's wort products containing hyperforin 1 mg or more (97171).

DIGOXIN (Lanoxin) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B St. John's wort reduces the levels and clinical effects of digoxin.  Details St. John's wort can reduce the bioavailability, serum levels, and therapeutic effects of digoxin. Taking an extract of St. John's wort 900 mg, containing hyperforin 7.5 mg or more, daily for 10-14 days, can reduce serum digoxin levels by 25% in healthy people. St. John's wort is thought to affect the multidrug transporter, P-glycoprotein, which mediates the absorption and elimination of digoxin and other drugs (382,6473,7808,7810,9204,96552,97171). St. John's wort products providing less than 7.5 mg of hyperforin daily do not appear to affect digoxin levels (97171).

DOCETAXEL (Taxotere) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B St. John's wort reduces the levels and clinical effects of docetaxel.  Details Clinical research shows that taking a specific St. John's wort product (Hyperiplant, VSM) 300 mg three times daily for 14 days increases docetaxel clearance by about 14%, resulting in decreased plasma concentrations of docetaxel in cancer patients. This is most likely due to induction of cytochrome P450 3A4 (CYP3A4) by St. John's wort (89661).

FENTANYL Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Theoretically, St. John's wort may reduce the levels and clinical effects of fentanyl.  Details Given that St. John's wort induces cytochrome P450 3A4 (CYP3A4) and P-glycoprotein, it is possible that concomitant use of St. John's wort with fentanyl will reduce plasma levels and analgesic activity of fentanyl (96552). However, some clinical research in healthy adults shows that taking St. John's wort (LI-160, Lichtwer Pharma) 300 mg daily for 21 days does not alter the pharmacokinetics or clinical effects of intravenous fentanyl (102868). It is unclear if these findings can be generalized to oral, intranasal, or transdermal fentanyl.

FEXOFENADINE (Allegra) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B St. John's wort may increase the levels and clinical effects of fexofenadine.  Details A single dose of St. John's wort decreases the clearance of fexofenadine and increases its plasma levels. However, the effect of St. John's wort on plasma levels of fexofenadine seems to be lost if dosing is continued for more than 2 weeks (9685). Patients taking fexofenadine and St. John's wort concurrently should be monitored for possible fexofenadine toxicity.

FINASTERIDE (Proscar, Propecia) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D St. John's wort may reduce the levels and clinical effects of finasteride.  Details St. John's wort reduces plasma levels of finasteride in healthy male volunteers due to induction of finasteride metabolism via cytochrome P450 3A4 (CYP3A4). The clinical significance of this interaction is not known (96552).

GLICLAZIDE (Diamicron, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B St. John's wort may reduce the levels and clinical effects of gliclazide.  Details Taking St. John's wort decreases the half-life and increases clearance of gliclazide in healthy people (22431).

HMG-CoA REDUCTASE INHIBITORS ("Statins") Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B St. John's wort may increase the metabolism and reduce the effectiveness of atorvastatin, lovastatin, and rosuvastatin. However, it does not seem to affect pravastatin, pitavastatin, or fluvastatin.  Details Concomitant use of St. John's wort can reduce plasma concentrations of the active simvastatin metabolite, simvastatin hydroxy acid, by 28%. St. John's wort induces intestinal and hepatic cytochrome P450 3A4 (CYP3A4) and intestinal P-glycoprotein/MDR-1, a drug transporter. This increases simvastatin clearance. It also increases the clearance of atorvastatin (Lipitor), lovastatin (Mevacor), and rosuvastatin (Crestor). St. John's wort does not seem to affect the plasma concentrations of pravastatin (Pravachol), pitavastatin (Livalo) or fluvastatin (Lescol), which are not substrates of CYP3A4 or P-glycoprotein (10627,96552,97171).

IMATINIB (Gleevec) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = A St. John's wort reduces the levels and clinical effects of imatinib.  Details Taking St. John's wort 900 mg daily for 2 weeks reduces the bioavailability and half-life of a single dose of imatinib and decreases its serum levels by 30% in healthy volunteers. This is most likely due to induction of cytochrome P450 3A4 (CYP3A4) by St. John's wort, which increases clearance of imatinib (11888,96552).

INDINAVIR (Crixivan) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D St. John's wort may reduce the levels and clinical effects of indinavir.  Details In healthy volunteers, taking St. John's wort concurrently with indinavir reduces plasma concentrations of indinavir by inducing metabolism via cytochrome P450 3A4 (CYP3A4) (96552). Theoretically, this could result in treatment failure and viral resistance.

IRINOTECAN (Camptosar) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = A St. John's wort reduces the levels and clinical effects of irinotecan.  Details St. John's wort 900 mg daily for 18 days decreases serum levels of irinotecan by at least 50%. Clearance of the active metabolite of irinotecan, SN-38, is also increased, resulting in a 42% decrease in the area under the concentration-time curve (9206,97171). This is thought to be due to induction of cytochrome P450 3A4 (CYP3A4) by St. John's wort (7092,96552).

IVABRADINE (Corlanor) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D St. John's wort might reduce the levels and clinical effects of ivabradine.  Details Taking St. John's wort 900 mg containing 7.5 mg of hyperforin daily for 14 days with a single dose of ivabradine causes a 62% reduction in plasma levels of ivabradine. This interaction is thought to be due to induction of cytochrome P450 3A4 (CYP3A4) by St. John's wort, increasing the metabolism of ivabradine (96552,97171).

KETAMINE (Ketalar) Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B St. John's wort reduces the levels and clinical effects of ketamine.  Details Taking St. John's wort 300 mg three times daily for 14 days can decrease maximum serum levels of ketamine by around 66% and area under the concentration-time curve of ketamine by 58%. This is most likely due to induction of cytochrome P450 3A4 (CYP3A4) by St. John's wort (89663).

MEPHENYTOIN (Mesantoin) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B St. John's wort reduces the levels and clinical effects of mephenytoin.  Details Preliminary clinical research in healthy males shows that taking St. John's wort for 14 days induces cytochrome P450 2C19 (CYP2C19) and significantly increases metabolism of mephenytoin (Mesantoin). In people with wild-type 2C19, metabolism was almost 4-fold greater in subjects who received St. John's wort compared to placebo. In contrast, patients with 2C19*2/*2 and *2/*3 genotypes did not demonstrate a similar increase in metabolism (17405).

METHADONE (Dolophine) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B St. John's wort might reduce the levels and clinical effects of methadone.  Details St. John's wort might decrease the effectiveness of methadone by reducing its blood concentrations. In one report, two out of four patients on methadone maintenance therapy for addiction experienced methadone withdrawal symptoms after taking St. John's wort 900 mg daily for a median of 31 days. There was a median decrease in blood methadone concentration of 47% (range: 19% to 60%) when compared to baseline (22419).

METHYLPHENIDATE (Concerta, others) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D St. John's wort might reduce the levels and clinical effects of methylphenidate.  Details St. John's wort might decrease the effectiveness of methylphenidate. In one report, an adult male, stabilized on methylphenidate for attention deficit-hyperactivity disorder (ADHD), experienced increased attention problems and ADHD symptoms after taking St. John's wort 600 mg daily for 4 months. ADHD symptoms improved when St. John's wort was discontinued (15544). The mechanism of this interaction is unknown.

NON-NUCLEOSIDE REVERSE TRANSCRIPTASE INHIBITORS (NNRTIs) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B St. John's wort decreases the levels and clinical effects of NNRTIs.  Details St. John's wort increases the oral clearance of nevirapine (Viramune) by 35%. Subtherapeutic concentrations are associated with therapeutic failure, development of viral resistance, and development of drug class resistance. St. John's wort induces intestinal and hepatic cytochrome P450 3A4 (CYP3A4) and intestinal P-glycoprotein/MDR-1, a drug transporter (1290,1340,4837,96552).

OMEPRAZOLE (Prilosec) Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B St. John's wort decreases the levels and clinical effects of omeprazole.  Details Taking St. John's wort, 300 mg orally three times daily for 14 days, reduces serum concentrations of omeprazole by inducing its metabolism via cytochrome P450 (CYP) 2C19 and 3A4. The reduction of omeprazole serum levels is dependent on CYP2C19 genotype, with reductions up to 50% in extensive metabolizers and 38% in poor metabolizers (22440,96552).

OXYCODONE (Oxycontin) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B St. John's wort decreases the levels and clinical effects of oxycodone.  Details St. John's wort can increase oxycodone metabolism by inducing cytochrome P450 3A4 (CYP3A4), reducing plasma levels and analgesic activity (96552).

P-GLYCOPROTEIN SUBSTRATES Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B St. John's wort decreases the levels and clinical effects of P-glycoprotein substrates.  Details St. John's wort induces P-glycoprotein. P-glycoprotein is a carrier mechanism responsible for transporting drugs and other substances across cell membranes. When P-glycoprotein is induced in the gastrointestinal (GI) tract, it can prevent the absorption of some medications. In addition, induction of p-glycoprotein can decrease entry of drugs into the central nervous system (CNS) and decrease access to other sites of action (382,1340,7810,11722).

PHENOBARBITAL (Luminal) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B St. John's wort decreases the levels and clinical effects of phenobarbital.  Details St. John's wort may increase the metabolism of phenobarbital. Plasma concentrations of phenobarbital should be monitored carefully. The dose of phenobarbital may need to be increased when St. John's wort is started and decreased when it is stopped (9204).

PHENPROCOUMON (Marcoumar, others) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B St. John's wort decreases the levels and clinical effects of phenprocoumon.  Details St. John's wort appears to increase the metabolism of phenprocoumon (an anticoagulant that is not available in the US) by increasing the activity of the cytochrome P450 2C9 (CYP2C9) enzyme. This may result in decreases in the anticoagulant effect and international normalized ratio (INR) (9204).

PHENYTOIN (Dilantin) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B St. John's wort decreases the levels and clinical effects of phenytoin.  Details St. John's wort may increase the metabolism of phenytoin. Plasma concentrations of phenytoin should be monitored closely. The dose of phenytoin may need to be increased when St. John's wort is started and decreased when it is stopped (9204).

PHOTOSENSITIZING DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, St. John's wort might increase the likelihood for photosensitivity reactions when used in combination with photosensitizing drugs.  Details St. John's wort might increase photosensitivity reactions due to its hypericin content (166,111644). However, some clinical research shows that very high doses of St. John's wort are needed to produce phototoxicity in humans (3900,4542,76266).

PROCAINAMIDE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, St. John's wort might decrease the levels and clinical effects of procainamide.  Details Animal research shows that taking St. John's wort extract increases the bioavailability of procainamide, but does not increase its metabolism (14865). Whether this interaction is clinically significant in humans is not known.

PROTEASE INHIBITORS (PIs) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B St. John's wort reduces the levels and clinical effects of PIs.  Details In healthy volunteers, St. John's wort can reduce the plasma concentrations of indinavir (Crixivan) by inducing cytochrome P450 3A4 (CYP3A4). This might result in treatment failure and viral resistance (1290,7808,96552). St. John's wort also induces P-glycoprotein, which can result in decreased intracellular protease inhibitor concentrations and increased elimination (9204).

RESERPINE (Raudixin, others) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, St. John's wort might decrease the effectiveness of reserpine.  Details Animal research shows that St. John's wort can antagonize the effects of reserpine (758).

RIVAROXABAN (Xarelto) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B St. John's wort decreases the levels and clinical effects of rivaroxaban.  Details A small pharmacokinetic study in healthy volunteers shows that taking a single dose of rivaroxaban 20 mg after using a specific St. John's wort extract (Jarsin, Vifor SA) 450 mg orally twice daily for 14 days reduces the bioavailability of rivaroxaban by 24% and reduces rivaroxaban's therapeutic inhibition of factor Xa by 20% (104038).

SEROTONERGIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, St. John's wort might inhibit reuptake and increase levels of serotonin, resulting in additive effects with serotonergic drugs.  Details Concomitant use of serotonergic drugs with St. John's wort can lead to increased adverse effects and increase the risk of serotonergic side effects, including serotonin syndrome and cerebral vasoconstriction disorders (166,542,3569,8056,110318).

TACROLIMUS (Prograf) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B St. John's wort decreases the levels and clinical effects of tacrolimus.  Details Taking a St. John's wort extract (Jarsin) 600 mg daily significantly decreases tacrolimus serum levels. Dose increases of 60% may be required to maintain therapeutic tacrolimus levels in patients taking St. John's wort. St. John's wort is thought to lower tacrolimus levels by inducing cytochrome P450 3A4 (CYP3A4) enzymes (7095,10329). A small clinical study in healthy adults also shows that taking St. John's wort 300 mg three times daily for 10 days decreases the total systemic exposure to tacrolimus by 27% and 33% after taking a single 5 mg dose of immediate-release or prolonged-release tacrolimus, respectively (113094).

THEOPHYLLINE Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Unlikely •  Level of Evidence = D St. John's wort might decrease the levels of theophylline, although this effect might not be clinically relevant.  Details St. John's wort does not seem to significantly affect theophylline pharmacokinetics (11802). There is a single case report of a possible interaction with theophylline. A patient who smoked and was taking 11 other drugs experienced an increase in theophylline levels after discontinuation of St. John's wort. This increase has been attributed to a rebounding of theophylline serum levels after St. John's wort was no longer present to induce metabolism via cytochrome P450 1A2 (CYP1A2) (3556,7808,9204). However, studies in healthy volunteers show that St. John's wort is unlikely to affect theophylline to any clinically significant degree (11802).

TRAMADOL (Ultram) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D St. John's wort might decrease the levels and clinical effects of tramadol.  Details St. John's wort can increase tramadol metabolism via induction of cytochrome P450 3A4 (CYP3A4), reducing plasma levels and analgesic activity (96552). Theoretically, concurrent use of St. John's wort with tramadol might also cause additive serotonergic effects (763,6427,8056,8936).

VORICONAZOLE (Vfend) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B St. John's wort might decrease the levels and clinical effects of voriconazole.  Details Clinical research shows that taking St. John's wort with voriconazole reduces voriconazole exposure and increases voriconazole metabolism by approximately 107%. Voriconazole is primarily metabolized by cytochrome P450 (CYP) 2C19, with CYP3A4 and CYP2C9 also involved (89660). St. John's wort induces CYP2C19, CYP3A4, and CYP2C9 (9204,10830,10847,10848,11889,11890,17405,22423,22424,22425)(22427,48603).

WARFARIN (Coumadin) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B St. John's wort decreases the levels and clinical effects of warfarin.  Details Taking St. John's wort significantly increases clearance of warfarin, including both its R- and S-isomers (11890,15176). This is likely due to induction of cytochrome P450 (CYP) 1A2 and CYP3A4 (11890). St. John's wort can also significantly decrease International Normalized Ratio (INR) in people taking warfarin (1292). In addition, taking warfarin at the same time as St. John's wort might reduce warfarin bioavailability. When a dried extract is mixed with warfarin in an aqueous medium, up to 30% of warfarin is bound to particles, reducing its absorption (10448).

ZOLPIDEM (Ambien) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B St. John's wort might decrease the levels and clinical effects of zolpidem.  Details In clinical research, concomitant use of zolpidem with St. John's wort decreased zolpidem plasma levels due to induction of its metabolism by cytochrome P450 3A4 (22441,96552). Whether this interaction is clinically significant is not known.

(Read more about ST. JOHN'S WORT)

ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Taking tribulus with antidiabetes drugs might increase the risk of hypoglycemia.  Details Clinical research shows that Tribulus can lower blood glucose levels in adults with type 2 diabetes who are taking antidiabetes medications (97327).

ANTIHYPERTENSIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking tribulus with antihypertensive drugs might increase the risk of hypotension.  Details Animal research shows that tribulus can lower blood pressure by inhibiting angiotensin-converting enzyme (ACE) (12673). Tribulus has also demonstrated hypotensive effects in pre-hypertensive adults (105245).

LITHIUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, tribulus might increase the levels and clinical effects of lithium.  Details Tribulus is thought to have diuretic properties (12681). Due to these potential diuretic effects, tribulus might reduce excretion and increase levels of lithium. The dose of lithium might need to be decreased.

(Read more about TRIBULUS)

ANTIPSYCHOTIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, vitex agnus-castus could interfere with the activity of antipsychotic drugs.  Details Vitex agnus-castus might interfere with the action of dopamine antagonists such as antipsychotic drugs due to its dopamine agonist effects (7014,7015).

CONTRACEPTIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Theoretically, vitex agnus-castus could interfere with oral contraceptives.  Details Vitex agnus-castus might interfere with the efficacy of oral contraceptives due to possible hormone modulating activity (10979,11456).

DOPAMINE AGONISTS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, vitex agnus-castus could interfere with dopamine agonists.  Details Vitex agnus-castus might potentiate the actions of dopaminergic agonists due to possible dopaminergic effects (10122).

ESTROGENS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, vitex agnus-castus could interfere with the activity of estrogens.  Details Vitex agnus-castus has hormone modulating activity that can interfere with the efficacy of hormone replacement therapy (10979,11456).

METOCLOPRAMIDE (Reglan) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, dopaminergic effects of vitex agnus-castus could interfere with metoclopramide.  Details Vitex agnus-castus might interfere with the action of dopamine antagonists such as metoclopramide due to its possible dopaminergic effects (7014,7015).

(Read more about VITEX AGNUS-CASTUS)

ESTROGENS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, wild yam might increase or decrease the effects of estrogen.  Details Wild yam root shows estrogenic and anti-estrogenic effects in vitro (6180,70411,96723,96725). Theoretically, wild yam might interfere with hormone therapy.

(Read more about WILD YAM)

General ...Orally, black pepper seems to be well tolerated when used in the amounts found in food or when taken as a medicine as a single dose. Topically and as aromatherapy, black pepper oil seems to be well tolerated.
Most Common Adverse Effects:
Orally: Burning aftertaste, dyspepsia, and reduced taste perception.
Inhalation: Cough.
Serious Adverse Effects (Rare):
Orally: Allergic reaction in sensitive individuals.

Gastrointestinal ...Orally, black pepper can cause a burning aftertaste (5619) and dyspepsia (38061). Single and repeated application of piperine, the active constituent in black pepper, to the tongue and oral cavity can decrease taste perception (29267). By intragastric route, black pepper 1.5 grams has been reported to cause gastrointestinal microbleeds (29164). It is not clear if such an effect would occur with oral administration.

Immunologic ...In one case report, a 17-month-old male developed hives, red eyes, facial swelling, and a severe cough following consumption of a sauce containing multiple ingredients. Allergen skin tests were positive to both black pepper and cayenne, which were found in the sauce (93947).

Ocular/Otic ...Topically, ground black pepper can cause redness of the eyes and swelling of the eyelids (5619).

Pulmonary/Respiratory ...When inhaled through the nose as an olfactory stimulant, black pepper oil has been reported to cause cough in one clinical trial (29162).

(Read more about BLACK PEPPER)

General ...Orally, adverse effects to damiana seem to be rare; however, a thorough safety evaluation has not been conducted.

Neurologic/CNS ...Orally, 200 grams of damiana extract has caused tetanus-like convulsions and paroxysms resulting in symptoms similar to rabies or strychnine poisoning (4).

(Read more about DAMIANA)

General ...Orally, dong quai is generally well-tolerated.
Most Common Adverse Effects:
Orally: Burping and flatulence.
Intravenously: Headache.

Cardiovascular ...Orally, dong quai might cause hypertension; according to one case report, a parent and breastfed infant experienced hypertension (195/85 mmHg and 115/69 mmHg, respectively) after the parent consumed a soup containing dong quai root (48428).

Dermatologic ...Dong quai contains psoralens that may cause photosensitivity and photodermatitis (10054,10057,48461).

Endocrine ...In a case report, a male developed gynecomastia after ingesting dong quai tablets (48504).

Gastrointestinal ...Orally, burping and gas may occur with dong quai (738).

Hematologic ...In one case report, a 55-year-old female with protein S deficiency and systemic lupus erythematosus (SLE) had temporary vision loss in the left eye from hemiretinal vein thrombosis three days after taking a phytoestrogen preparation containing dong quai 100 mg, black cohosh 250 mg, wild Mexican yam 276 mg, and red clover 250 mg (13155). It is unclear if dong quai contributed to this event.

Neurologic/CNS ...Dong quai given orally or by injection may be associated with headache (738,48438).

Oncologic ...Dong quai contains constituents that are carcinogenic; however, whether these constituents are present in concentrations large enough to cause cancer with long-term or high-dose use is unknown (7162).

Pulmonary/Respiratory ...A pharmacist experienced allergic asthma and rhinitis after occupational exposure to dong quai and other herbs (48435).

(Read more about DONG QUAI)

General ...Orally, kava seems to be well tolerated.
Most Common Adverse Effects:
Orally: Drowsiness, dry mouth, dizziness, gastrointestinal upset, headache, memory problems, tremor.
Serious Adverse Effects (Rare):
Orally: There have been over 100 reported cases of hepatotoxicity and a few reported cases of rhabdomyolysis.

Cardiovascular ...Long-term use of very large amounts of kava, especially in high doses (400 mg kava pyrones daily), has been associated with overall poor health including symptoms of low body weight, reduced protein levels, puffy face, hematuria, increased red blood cell volume, decreased platelets and lymphocytes, and possibly pulmonary hypertension (4032,6402). Tachycardia and electrocardiogram (ECG) abnormalities (tall P waves) have been reported in heavy kava users (6402).

Dermatologic ...Orally, kava can cause allergic skin reactions, including sebotropic eruptions, delayed-type hypersensitivity, or urticarial eruption (4032,11370,28489,57277,57325,57343,114683). In one case of kava-associated urticarial eruption, biopsy revealed neutrophilic sebaceous glands with lymphocytic infiltrate (114683). Chronic use of high doses of kava has also been associated with kava dermopathy, which consists of reddened eyes; dry, scaly, flaky skin; and temporary yellow discoloration of the skin, hair, and nails (6240,6401,8414,8417,11370,28485,57342). This pellagra-like syndrome is unresponsive to niacinamide treatment (6240,7728,11370). The cause is unknown, but may relate to interference with cholesterol metabolism (6240). Kava's adverse effects on liver function might also contribute to kava dermopathy (6401,8417). Kava dermopathy usually occurs within three months to one year of regular kava use, and resolves when the kava dose is decreased or discontinued (6401,8414). Kava dose should be decreased or discontinued if kava dermopathy occurs (6401). In addition to kava cessation, oral or topical corticosteroids have been described as treatment options in some cases of kava associated dermatitis (114683).

Gastrointestinal ...Orally, kava may cause gastrointestinal upset, nausea, or dry mouth (2093,2094,4032,11370,18316,57228,57343).

Hematologic ...Orally, chronic use of very high doses of kava has been associated with increased red blood cell volume, reduced platelet volume, reduced lymphocyte counts, and reduced serum albumin (6402,57258). Hematuria has also been reported anecdotally (6402).

Hepatic ...Since the early 2000's, hepatotoxicity has been a particular concern with kava. Worldwide, there have been at least 100 reported cases of hepatotoxicity following use of kava products (7024,7068,7086,7096,11795,17086)(57252,57254,57297). However, some experts question the clinical validity of several of these cases (11369,11371). Some cases were reported multiple times and in some cases it was unlikely that kava was the causative agent (7068,57253).
In susceptible patients, symptoms can show up after as little as 3-4 weeks of kava use. Symptoms include yellowed skin (jaundice), fatigue, and dark urine (7024,7068). Liver function tests can be elevated after 3-8 weeks of use, possibly followed by hepatomegaly and onset of encephalopathy (7024). Kava has also been reported to exacerbate hepatitis in patients with a history of recurrent hepatitis (390). However, in many cases, symptoms seem to resolve spontaneously, and liver function tests usually normalize within eight weeks (390,7068).
Liver toxicity is more frequently associated with prolonged use of very high doses (6401,57346). But there is some concern that even short-term use of kava in typical doses might cause acute hepatitis in some patients, including severe hepatocellular necrosis. The use of kava for as little as 1-3 months has resulted in need for liver transplant and death, although these events are rare (7024,7068,7086,7096,17086).
There is some speculation that the type of extraction method could be responsible for these rare cases of hepatotoxicity (17086). The "Pacific kava paradox" holds that while the alcohol and acetone extracts of kava used for commercial products cause liver toxicity, the traditional kava rhizome preparation mixed with water might not be toxic (11794,17086). However, a more recent analysis reports cases of hepatotoxicity from the aqueous kava extract and suggests that kava's hepatotoxic effects may be due to contaminants such as mold (29676). Other suggested causes of hepatotoxicity include quality of the kava plant, concomitant medications, large doses and prolonged use, and toxic constituents and metabolites of kava (57300,88532).
Some commercial kava extracts contain parts of the stems and other aerial parts in addition to the rhizome, and it has been suggested that a constituent called pipermethysine, which is only found in these aerial parts, might be partly responsible for hepatotoxicity (17086). Other constituents of kava which might contribute to hepatotoxicity are kavalactones, which are metabolized by cytochrome P450 (CYP450) enzymes in the liver. Reactive metabolites are produced which conjugate with glutathione, and might deplete glutathione in a similar manner to acetaminophen (17086). Increased levels of gamma-glutamyl transferase, involved in the production of glutathione, have been reported in chronic kava users (17086). One of the enzymes involved in production of reactive metabolites from kavalactones is cytochrome P450 2E1 (CYP2E1), which is induced by chronic alcohol intake. Alcohol may also compete for other enzymes which clear kavalactone metabolites from the body. This might explain the observation that alcohol ingestion seems to increase the risk of hepatotoxicity with kava (7068,17086).
There is also speculation that "poor metabolizers" or those patients with deficiency in the cytochrome P450 2D6 (CYP2D6) isoenzyme, which occurs in up to 10% of people of European descent, may be at increased risk for hepatotoxic effects from kava (7068). This deficiency has not been found in Pacific Islanders. However, this theory has not been confirmed.
Due to the concerns regarding the potential hepatotoxicity of kava, kava supplements were withdrawn from European and Canadian markets in 2002 (7086). However, many of the market withdrawals of kava have been lifted after re-evaluation of kava suggested that the risk of hepatotoxicity was minimal (91593,91594,91615). Still, clinical practice guidelines from a joint taskforce of the World Federation of Societies of Biological Psychiatry (WFSBP) and the Canadian Network for Mood and Anxiety Treatments (CANMAT) recommend exercising caution when using kava in patients with preexisting liver issues (110318). Until more is known, tell patients to use kava cautiously and recommend liver function tests for routine users or those with underlying liver disease.

Immunologic ...Sjögren syndrome has been associated with an herbal supplement containing kava, echinacea, and St. John's wort. Echinacea may have been the primary cause, because Sjögren syndrome is an autoimmune disorder. The role of kava in this syndrome is unclear (10319).

Musculoskeletal ...Kava has been linked with reports of rhabdomyolysis. A 34-year-old man who consumed kava tea several times a week developed rhabdomyolysis with a peak creatine kinase level of 32,500 units/liter (18212). However, there is speculation that this might have been due to product impurities rather than kava itself. Another case report describes rhabdomyolysis with myoglobinuria and a creatine kinase level of 100,500 units/liter in a 29-year-old man who had taken kava in combination with guarana and ginkgo biloba (18213).
Cases of ataxia and tremors have been reported in patients taking single doses of kava powder 205 grams (11373).

Neurologic/CNS ...Orally, kava may cause headache, dizziness, and drowsiness (4032,6402,11370,11372,11373,18316,112642). It might also cause extrapyramidal side effects such as involuntary oral and lingual reflexes, twisting movements of the head and trunk, tremors, and other parkinsonian-like symptoms possibly due to dopamine antagonism (534,4055,7727,8415,102086). In one clinical trial, patients taking a kava supplement providing 120 mg of kavalactones twice daily for 16 weeks had a 3.2-fold greater risk of experiencing tremors when compared with patients taking placebo (102086). Theoretically, kava may worsen symptoms in patients with Parkinson disease or precipitate Parkinson-like symptoms in certain patients (4055,7727). Unlike benzodiazepines, kava is not thought to be associated with impaired cognitive function (2097,2098,11373,57332,57333). However, one clinical trial shows that taking a kava supplement providing 120 mg of kavalactones twice daily for 16 weeks increases the risk for memory impairment by 55% when compared with placebo (102086).
Orally, kava may reduce alertness and impair motor coordination in a dose-dependent manner. Some preliminary reports have noted a decline in accuracy of visual attention and slower reaction times after kava ingestion, particularly at higher doses and in combination with alcohol (11373,95926). Population research has also found that ingesting large amounts of kava tea (typically 50 times higher than what is used medicinally in the US) within a 12-hour period before driving increases the odds of being involved in a serious motor vehicle crash resulting in death or serious injury by almost 5-fold when compared to not drinking kava tea (95927). Use of normal doses of kava may also affect the ability to drive or operate machinery, and driving under the influence (DUI) citations have been issued to individuals observed driving erratically after drinking large amounts of kava tea (535). However, in computer-based driving simulator tests, there are no reported adverse effects of kava on performance (95926). Additionally, other research shows that consuming over 4400 mg of kavalactones over a 6-hour kava session does not seem to impair alertness or attention when compared with non-kava drinkers (103867). Similar research using a specific psychometric tool (Brain Gauge) shows that consuming approximately 3680 mg of kavalactones in a 6-hour kava session seems to impair temporal order judgment, which is associated with the brain's ability to track the order of events, when compared with non-kava drinkers. However, it does not seem to impact cognitive domains related to focus, accuracy, timing perception, plasticity, or fatigue when compared with non-kava drinkers (110435).

Ocular/Otic ...Orally, high doses of kava may cause eye irritation (7728). There is one case report of impaired accommodation and convergence, increased pupil diameter, and oculomotor disturbance following a single dose of kava (9920).

Psychiatric ...Apathy has been associated with traditional use of kava at high doses (57313).

Pulmonary/Respiratory ...Orally, kava may cause shortness of breath, possibly due to pulmonary hypertension (6402).

Renal ...Orally, kava may cause acute urinary retention (57349).

(Read more about KAVA)

General ...Orally, no adverse effects have been reported with the medicinal use of maca. However, a thorough evaluation of safety outcomes has not been conducted.

Gastrointestinal ...Consumption of fresh, uncooked maca may cause stomach pain (40231).

(Read more about MACA)

General ...No adverse effects have been reported. However, a thorough evaluation of safety outcomes has not been conducted.

(Read more about MUIRA PUAMA)

General ...Orally, niacin is well tolerated in the amounts found in foods. It is also generally well tolerated in prescription doses when monitored by a healthcare provider.
Most Common Adverse Effects:
Orally: Flushing, gastrointestinal complaints (abdominal pain, constipation, diarrhea, heartburn, nausea, vomiting), and elevated liver enzymes.
Serious Adverse Effects (Rare):
Orally: Hepatotoxicity, myopathy, thrombocytopenia, and vision changes.

Cardiovascular ...Orally, flushing is a common dose-related adverse reaction to niacin. A large meta-analysis of clinical studies shows that up to 70% of patients may experience flushing (96211). Although flushing can occur with doses of niacin as low as 30 mg daily, it is more common with the larger doses used for treatment of dyslipidemia. The flushing reaction is due to prostaglandin-induced blood vessel dilation and can also include symptoms of burning, tingling, urticaria, erythema, pain, and itching of the face, arms, and chest. There may also be increased intracranial blood flow and headache (4889,26089,93341,104933). Onset is highly variable and ranges from within 30 minutes to as long as 6 weeks after the initial dose (6243). Flushing can be minimized via various strategies, including taking doses with meals, slow dose titration, using extended release formulations, pretreating with non-steroidal anti-inflammatory drugs, taking regular-release niacin with meals, or taking the sustained-release product at bedtime (4852,4853,4854,4857,4858,25922,26073,26084). Flushing often diminishes with continued use but can recur when niacin is restarted after missed doses (4863,6243,26081). The vasodilating effects of niacin can also cause hypotension, dizziness, tachycardia, arrhythmias, syncope, and vasovagal attacks, especially in patients who are already taking antihypertensive drugs (4863,12033,93341,110494).
High doses of niacin can raise homocysteine levels. A 17% increase has been reported with 1 gram daily and a 55% increased has been reported with 3 grams daily. Elevated homocysteine levels are an independent risk factor for cardiovascular disease (490); however, the clinical significance of this effect is unknown. A large-scale study (AIM-HIGH) found that patients receiving extended-release niacin (Niaspan) 1500-2000 mg daily with a statin had an over two-fold increased risk of ischemic stroke (1.6%) when compared with those receiving only simvastatin (0.7%). However, when the risk was adjusted for confounding factors, niacin was not found to be associated with increased stroke risk (17627,93354). A meta-analysis of three clinical trials conducted in approximately 29,000 patients showed a higher risk of mortality in patients taking niacin in addition to a statin when compared with a statin alone. However, with a p-value of 0.05 and confidence interval including 1, the validity of this finding remains unclear (97308).

Endocrine ...Orally, niacin can impair glucose tolerance in a dose-dependent manner. Dosages of 3-4 grams daily appear to increase blood glucose in patients with or without diabetes, while dosages of 1.5 grams daily or less have minimal effects (12033). Niacin is thought to impair glucose tolerance by increasing insulin resistance or increasing hepatic output of glucose (4863,11692,11693). In patients with diabetes, niacin 4.5 grams daily for 5 weeks has been associated with an average 16% increase in plasma glucose and 21% increase in glycated hemoglobin (HbA1C) (4860). Up to 35% of patients with diabetes may need to increase the dose or number of hypoglycemic agents when niacin is started (4458,4860,4863,11689,12033). Occasionally, severe hyperglycemia requiring hospitalization can occur (11693). In patients with impaired fasting glucose levels, niacin may also increase fasting blood glucose, and adding colesevelam might attenuate this effect (93343).
Although patients without diabetes seem to only experience small and clinically insignificant increases in glucose (4458), niacin might increase their risk of developing diabetes. A meta-analysis of clinical research involving over 26,000 patients shows that using niacin over 5 years is associated with increased prevalence of new onset type 2 diabetes at a rate of 1 additional case of diabetes for every 43 patients treated with niacin (96207). This finding is limited because the individual trials were not designed to assess diabetes risk and the analysis could not be adjusted for confounding factors like obesity. One small clinical study shows that taking extended-release niacin with ezetimibe/simvastatin does not increase the risk of a new diagnosis of diabetes or need for antidiabetic medication when compared with ezetimibe/simvastatin alone after 16 months (93344). This may indicate that the increased risk of developing diabetes is associated with niacin use for more than 16 months.
Niacin therapy has also been linked with hypothyroidism and its associated alterations in thyroid hormone and binding globulin tests (such as decreased total serum thyroxine, increased triiodothyronine, decreased thyroxine-binding globulin levels, and increased triiodothyronine uptake) (25916,25925,25926,25928).

Gastrointestinal ...Orally, large doses of niacin can cause gastrointestinal disturbances including nausea, vomiting, bloating, heartburn, abdominal pain, anorexia, diarrhea, constipation, and activation of peptic ulcers (4458,4863,12033,26083,93341,96211). These effects may be reduced by taking the drug with meals or antacid, and usually disappear within two weeks of continued therapy (4851,26094). Gastrointestinal effects may be more common with time-release preparations of niacin (11691).

Hematologic ...Orally, sustained-release niacin has been associated with cases of reversible coagulopathy, mild eosinophilia, and decreased platelet counts (4818,25915,26097,93340). Also, there have been reports of patients who developed leukopenia while taking niacin for the treatment of hypercholesterolemia (25916).

Hepatic ...Orally, niacin is associated with elevated liver function tests and jaundice, especially with doses of 3 grams/day or more, and when doses are rapidly increased (4458,4863,6243). The risk of hepatotoxicity appears to be higher with slow-release and extended-release products (4855,4856,4863,6243,11691,12026,12033,93342). Niacin should be discontinued if liver function tests rise to three times the upper limit of normal (4863). There are rare cases of severe hepatotoxicity with fulminant hepatitis and encephalopathy due to niacin (4863,6243,11691). In one case, a patient taking extended-release niacin 2500 mg daily for 15 years developed decompensating cirrhosis and was diagnosed with chronic, toxic, metabolic liver injury. Despite medical intervention, the patient died (113553). Also, there is at least one case of niacin-induced coagulopathy resulting from liver injury without liver enzyme changes (93340).

Musculoskeletal ...Orally, niacin has been associated with elevated creatine kinase levels (4818,4888). Also, several cases of niacin-induced myopathy have been reported (26100,26111). Concomitant administration of niacin and HMG-CoA reductase inhibitors may increase the risk of myopathy and rhabdomyolysis (14508,25918,26111); patients should be monitored closely.

Neurologic/CNS ...Orally, high-dose niacin has been associated with cases of neuropsychiatric adverse events such as extreme pain and psychosis. Two 65-year-old males taking niacin orally for 5 months for the treatment of dyslipidemias developed severe dental and gingival pain. The pain was relieved by the discontinuation of niacin. The pain was thought to be due to inflammation and pain referral to the teeth (4862). In one case report, a 52-year-old male with no history of psychiatric illness who initially complained of hot flushes when taking niacin 500 mg daily, presented with an acute psychotic episode involving mania after niacin was increased to 1000 mg daily (93350).

Ocular/Otic ...Orally, chronic use of large amounts of niacin has been associated with dry eyes, toxic amblyopia, blurred vision, eyelid swelling, eyelid discoloration, loss of eyebrows and eyelashes, proptosis, keratitis, macular edema, and cystic maculopathy, which appear to be dose-dependent and reversible (4863,6243,26112).

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General ...Orally, oats are well tolerated.
Most Common Adverse Effects:
Orally: Abdominal distension, bloating, flatulence, and unpleasant taste.
Topically: Burning, contact dermatitis, itching, and redness.

Dermatologic ...Topically, oat-containing preparations can cause contact dermatitis (12515). Redness, burning, and itchiness have also been reported (103340).

Gastrointestinal ...When consumed orally, oats provide fiber. Increasing fiber in the diet can cause flatulence, bloating, abdominal distention, and unpleasant taste. To minimize side effects, doses should be slowly titrated to the desired level. These adverse effects usually subside with continued use (12514).
In patients who have difficulty chewing food, or those with conditions that decrease small bowel motility, oat bran may cause bezoars (concretions) and intestinal obstruction. Oats and oat bran are unlikely to cause obstruction without other causative factors (4979,4985).

Immunologic ...In a case report, a 45-year-old male developed acute generalized urticaria, facial angioedema, and dyspnea immediately after consuming oat flour. The reaction resolved after emergency care for anaphylaxis. Further investigation revealed an IgE-mediated hypersensitivity reaction to oat proteins (113490).

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General ...Orally, St. John's wort is generally well tolerated.
Most Common Adverse Effects:
Orally: Diarrhea, dizziness, dry mouth, gastrointestinal discomfort (mild), fatigue, headache, insomnia, restlessness, and sedation.
Topically: Skin rash and photodermatitis.
Serious Adverse Effects (Rare):
Orally: There have been rare case reports of suicidal ideation and psychosis after taking St. John's wort.

Cardiovascular ...In clinical research, palpitations have been reported for patients taking St. John's wort orally, although the number of these events was higher for the patients taking sertraline (76070). In one case report, an adult female developed recurrent palpitations and supraventricular tachycardia (SVT) within 3 weeks of initiating St. John's wort 300 mg daily. SVT and related symptoms responded to Valsalva maneuvers and did not recur after discontinuing therapy (106051).
Edema has also been reported in clinical research for some patients treated with St. John's wort 900-1500 mg daily for 8 weeks (10843). Cardiovascular collapse following induction of anesthesia has been reported in an otherwise healthy patient who had been taking St. John's wort for 6 months (8931). A case of St. John's wort-induced hypertension has been reported for a 56-year-old patient who used St. John's wort extract 250 mg twice daily for 5 weeks. Blood pressure normalized after discontinuation of treatment (76073). A case of new-onset orthostatic hypotension and light-headedness has been reported for a 70 year-old homebound patient who was taking multiple prescription medications and herbal products, including St. John's wort (76128). When all herbal products were discontinued, these symptoms improved, and the patient experienced improvement in pain control.

Dermatologic ...Both topical and chronic oral use of St. John's wort can cause photodermatitis (206,620,758,4628,4631,6477,13156,17986,76072,76148)(95506,110318). The average threshold dose range for an increased risk of photosensitivity appears to be 1.8-4 grams St. John's wort extract or 5-10 mg hypericin, daily. Lower doses might not cause this effect (4542,7808). For example, a single dose of St. John's wort extract 1800 mg (5.4 mg hypericin) followed by 900 mg (2.7 mg hypericin) daily does not seem to produce skin hypericin concentrations thought to be high enough to cause phototoxicity (3900,4542,76266). Females appear to have a higher risk of dose-related photosensitivity. In a dose-ranging, small clinical trial, almost all of the female participants experienced mild to moderate photosensitivity with paresthesia in sun-exposed skin areas after administration of St. John's wort (Jarsin, Casella Med) 1800 mg daily for 3-6 days. Symptoms resolved about 12-16 days after discontinuation (95506). Male participants reported no adverse effects at this dose, and both genders reported no adverse effects at lower doses. Light or fair-skinned people should employ protective measures against direct sunlight when using St. John's wort either topically or orally (628).
Total body erythroderma without exposure to sunlight, accompanied by burning sensation of the skin, has also been reported (8930). Orally, St. John's wort may cause pruritus or skin rash, although these events seem to occur infrequently (76140,76148,76245). A case of persistent scalp and eyebrow hair loss has been reported for a 24-year-old schizophrenic female who was taking olanzapine plus St. John's wort 900 mg/day orally (7811). Also, a case of surgical site irritation has been reported for a patient who applied ointment containing St. John's wort (17225).

Endocrine ...A case of syndrome of inappropriate secretion of antidiuretic hormone (SIADH) in a 67-year-old male with depression has been reported. During a 3-month period, the patient was taking St. John's wort 300 mg daily then increased to 600-900 mg daily with no adverse effects despite a low serum sodium level of 122mEq/L, elevated levels of urine sodium, and urine osmolality suggestive of SIADH. St. John's wort appeared to be the only contributing factor. The patient's sodium level normalized 3 weeks after discontinuation of St. John's wort (95508).

Gastrointestinal ...Orally, St. John's wort may cause dyspepsia, anorexia, diarrhea, nausea, vomiting, and constipation, although these events seems to occur infrequently (4897,13021,17986,76070,76071,76113,76146,76150,76271).

Genitourinary ...Orally, St. John's wort can cause intermenstrual or abnormal menstrual bleeding (1292,76056). However, this effect has occurred in patients who were also taking an oral contraceptive. Changes in menstrual bleeding might be the result of a drug interaction (1292,76056). Also, St. John's wort has been associated with anorgasmia and frequent urination when used orally (10843,76070).
Sexual dysfunction can occur with St. John's wort, but less frequently than with SSRIs (10843). A case of erectile dysfunction and orgasmic delay has been reported for a 49-year-old male after taking St. John's wort orally for one week. Co-administration of sildenafil 25-50 mg prior to sexual activity reversed the sexual dysfunction. Previously, the patient had experienced orgasmic delay, erectile dysfunction, and inhibited sexual desire when taking a selective serotonin reuptake inhibitor (sertraline) (4836).

Hepatic ...A case of acute hepatitis with prolonged cholestasis and features of vanishing bile duct syndrome has been reported for a patient who used tibolone and St. John's wort orally for 10 weeks (76135). A case of jaundice with transaminitis and hyperbilirubinemia has been reported for a 79 year-old female who used St. John's wort and copaiba (95505). Laboratory values normalized 7 weeks after discontinuation of both products.

Musculoskeletal ...Orally, St. John's wort may cause muscle or joint stiffness, tremor, muscle spasms, or pain, although these events appear to occur rarely (76070).

Neurologic/CNS ...St. John's wort may cause headache, dizziness, fatigue, lethargy, or insomnia (5096,13021,76070,76071,76113,76132,76133,76150,89666). Isolated cases of paresthesia have been reported for patients taking St. John's wort (5073). A case of subacute toxic neuropathy has been reported for a 35-year-old female who took St. John's wort 500 mg daily orally for 4 weeks (621).

Ocular/Otic ...There is concern that taking St. John's wort might increase the risk of cataracts. The hypericin constituent of St. John's wort is photoactive and, in the presence of light, may damage lens proteins, leading to cataracts (1296,17088). In population research, people with cataracts were significantly more likely to have used St. John's wort compared to people without cataracts (17088). Ear and labyrinth disorders have been possibly attributed to use of St. John's wort in clinical research, although these events rarely occur (76120).

Psychiatric ...St. John's wort can induce hypomania in depressed patients and mania in depressed patients with occult bipolar disorder (325,3524,3555,3568,10845,76047,76064,76137,110318). Cases of first-episode psychosis have been reported for females who used St. John's wort orally. In both cases, symptoms resolved following discontinuation of St. John's wort and treatment with antipsychotics for several weeks (13015,89664). Also, psychosis and delirium have been reported for a 76-year-old female patient who used St. John's wort for 3 weeks. The patient may have been predisposed to this effect due to undiagnosed dementia (76270). Restlessness, insomnia, panic, and anxiety have been noted for some patients taking St. John's wort orally (5073,13156,76070,76132,76268,76269,89665).
In isolated cases, St. John's wort has been associated with a syndrome consisting of extreme anxiety, confusion, nausea, hypertension, and tachycardia. These symptoms may occur within 2-3 weeks after it is started, in patients with no other predisposing factors. This syndrome has been diagnosed as the serotonin syndrome (6201,7811,110318). In one case, the symptoms began after consuming tyramine-containing foods, including aged cheese and red wine (7812). In an isolated case, a 51-year-old female reported having had suicidal and homicidal thoughts for 9 months while taking vitamin C and a St. John's wort extract. Symptoms disappeared within 3 weeks of discontinuing treatment (76111). A case of decreased libido has been reported for a 42-year-old male with mood and anxiety disorders who had taken St. John's wort orally for 9 months (7312).
St. John's wort has been associated with withdrawal effects similar to those found with conventional antidepressants. Headache, nausea, anorexia, dry mouth, thirst, cold chills, weight loss, dizziness, insomnia, paresthesia, confusion, and fatigue have been reported. Withdrawal effects are most likely to occur within two days after discontinuation but can occur one week or more after stopping treatment in some people. Occurrence of withdrawal symptoms may not be related to dose or duration of use (3569,11801).

Pulmonary/Respiratory ...Orally, St. John's wort may cause sore throat, swollen glands, laryngitis, sinus ache, sweating, and hot flashes, although the frequency of these events appears to be similar to placebo (76150).

Renal ...Orally, St. John's wort has been associated with a case report of acute kidney failure in a 46-year-old female after one dose of homemade St. John's wort tea. Three sessions of hemodialysis were required before there was full recovery (106741). However, causality is unclear since the patient had also been taking diclofenac intermittently for a month prior to developing kidney failure.

Other ...Sjogren's syndrome has been reported in a patient taking herbal supplements including St. John's wort, echinacea, and kava. Echinacea may have been the primary cause, because Sjogren's syndrome is an autoimmune disorder. The role of St. John's wort in causing this syndrome is unclear (10319).

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General ...Orally, tribulus seems to be well tolerated.
Serious Adverse Effects (Rare):
Orally: Cases of liver and kidney injury, seizures, and chronic painful erection with impaired sexual function have been reported. Pneumothorax and bronchial polyp after consuming the spine-covered tribulus fruit have been reported.

Gastrointestinal ...Orally, tribulus can cause abdominal pain, cramping, nausea, vomiting, diarrhea, and constipation (92022,92027). However, in one study, the rates of these gastrointestinal complaints were similar for patients taking tribulus and those receiving placebo (92022).

Genitourinary ...In one case report, a patient taking two tribulus tablets (unknown dose) daily for 15 days presented to the local emergency department with a painful erection lasting 72 hours. The priapism was resolved with medical management; however, post-episode sexual function was impaired (92023).

Hepatic ...In one case report, a patient drinking tribulus water 2 liters daily for two days presented with lower limb weakness, seizures, hepatitis, and acute kidney injury. The patient's condition improved after hemodialysis and discontinuation of tribulus water (92069).

Neurologic/CNS ...Orally, tribulus has been reported to cause general excitation and insomnia. These symptoms were reversed upon discontinuation of the drug or decreasing the dose (78867). In one case report, a patient drinking tribulus water 2 liters daily for two days presented with lower limb weakness, seizures, hepatitis, and acute kidney injury. The patient's condition improved after hemodialysis and discontinuation of tribulus water (92069).

Pulmonary/Respiratory ...In one case report, a patient developed a bilateral pneumothorax after consuming the spine-covered fruit of tribulus (818). In another case report, a patient developed a polyp in the lobar bronchus of the right interior lobe due to the presence of a tribulus fruit spine (78852).

Renal ...In one case report, a patient drinking tribulus water 2 liters daily for two days presented with lower limb weakness, seizures, hepatitis, and acute kidney injury. The patient's condition improved after hemodialysis and discontinuation of the tribulus water (92069). In another case report, a healthy male taking one tribulus tablet (unknown dose) daily for a few months for bodybuilding purposes developed hyperbilirubinemia followed by acute kidney failure 2-3 weeks later. The patient was managed with intravenous fluids and a low-salt, low-protein diet (92025).

Other ...In one case report, gynecomastia was observed in a male weightlifter taking an herbal combination product containing tribulus. However, it is not clear if this adverse effect can be attributed to tribulus alone (78859).

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General ...Orally, vitex agnus-castus is generally well tolerated.
Most Common Adverse Effects:
Orally: Diarrhea, fatigue, headache, insomnia, irregular menstruation, nausea, skin irritation, stomach pain, vomiting.

Dermatologic ...Orally, skin conditions such as itching, irritation, urticaria, rash, acne, eczema, and hair loss have been reported (7055,7076,7078,7079,12207,13393,15065,90617,90619,101981).

Gastrointestinal ...Orally, gastrointestinal upset or pain, diarrhea, and nausea and vomiting, have been reported (7079,12207,13393,15065,90620,101981,101982). In one clinical trial, a single patient reported persistent gastroenteritis while taking vitex agnus-castus (7076). Orally, development of a bezoar resulting in colonic obstruction is described in a 63-year-old male who consumed an unknown amount of vitex agnus-castus seeds (111752).

Genitourinary ...Orally, irregular or prolonged menstrual bleeding has been reported (7055,7079,12207,13393,15065,41489,41490,95326).

Hematologic ...Orally, nosebleed has been reported in a single patient in a clinical trial (7079).

Immunologic ...Orally, multiple abscesses have been reported in a single patient (7055).

Neurologic/CNS ...Orally, headache, fatigue, and insomnia (7076,7078,12207,13393,13395,15065), confusion (90617), and vertigo (7079) have been reported.

Other ...Orally, weight gain has been reported (12207,13393,15065).

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General ...Orally, wild yam is generally well tolerated.
Most Common Adverse Effects:
Orally: Fever, headache, upset stomach, and vomiting.
Serious Adverse Effects (Rare):
Orally: Anaphylaxis.

Gastrointestinal ...Orally, wild yam can cause upset stomach and vomiting, especially at higher doses (12,86450).

Hematologic ...In one case report, a 55-year-old female with protein S deficiency and systemic lupus erythematosus (SLE) had temporary vision loss in the left eye from hemiretinal vein thrombosis 3 days after taking a combination phytoestrogen product containing wild yam 276 mg, dong quai 100 mg, red clover 250 mg, and black cohosh 250 mg (13155). It is unclear if wild yam contributed to this event.

Immunologic ...There are three case reports of anaphylaxis after ingestion of cooked wild yam (96722).

Neurologic/CNS ...Orally, wild yam can cause headache and fever, especially at higher doses (86450).

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