Lymph Essentials with LymphSelect Yellow Clover Extract [Discontinued] by Swanson Condition Specific Formulas

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.

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EFFECTIVE

• Migraine headache. Oral caffeine in combination with acetaminophen, aspirin, and/or sumatriptan is approved by the US Food and Drug Administration (FDA) for treating migraine headache. Details: Taking caffeine 100-260 mg orally in combination with acetaminophen 500-2000 mg, aspirin 500 mg, and/or sumatriptan 50-100 mg is effective for treating migraine headache (2715,2716,2717,37614,37626,37816,91068). Some evidence shows that caffeine in combination with aspirin and acetaminophen may be more effective than sumatriptan in treating a migraine attack (37666). However, taking caffeine 200 mg plus ergotamine seems to be less effective than sumatriptan or calcium carbasalate plus metoclopramide (37685,38312). Caffeine is an FDA-approved product for use with analgesics for the treatment of migraine.
• Neonatal apnea. Oral or intravenous caffeine citrate is approved by the US Food and Drug Administration (FDA) for the short-term treatment of neonatal apnea in very preterm infants. Details: Using caffeine orally or intravenously improves apnea of prematurity in very preterm infants and reduces the risk of bronchopulmonary dysplasia, invasive mechanical ventilation, and neurodevelopmental impairment (6023,6371,37857,37906,38124,38344,98807,100364). The dosage approved in the FDA labeling is a single loading dose of caffeine citrate 20 mg/kg (10 mg/kg caffeine base), followed by 5 mg/kg of caffeine citrate (2.5 mg/kg caffeine base) every 24 hours for maintenance. Clinical research shows that caffeine citrate dose-dependently reduces the number of apnea episodes by at least 50% over 7-10 days of treatment (6371). Doses above 10 mg/kg daily reduce the risk of apnea, bronchopulmonary dysplasia, and problematic extubation compared with doses below 10 mg/kg/day (98807,100364). Additional clinical research shows that reinitiating caffeine treatment after termination of the original caffeine regimen, and continuing until 40 weeks postmenstrual age, reduces the incidence of intermittent hypoxia in premature infants by 46% when compared to standard care (91073). At 18-21 months of age, a history of neonatal caffeine treatment reduces the risk of long-term complications of apnea of prematurity, such as cerebral palsy or cognitive delay (37722,38340). At 11 years of age, individuals born prematurely and treated with caffeine have improved visuomotor, visuoperceptual, and visuospatial abilities when compared to those who received placebo (97452). Data on the prophylactic use of caffeine in very low birth-weight infants (less than 1500 grams and 32 weeks' gestation) are conflicting. In a meta-analysis of 11 studies, 5 show a reduced risk of apnea of prematurity, oxygen therapy, bronchopulmonary dysplasia, patent ductus arteriosus, and retinopathy of prematurity, and a reduced duration of mechanical ventilation (111491). However, other studies do not show any benefit (38125,111491). A study of infants born at 34-36 weeks' gestation shows that caffeine citrate, 10 or 20 mg/kg orally daily, reduces the number of intermittent hypoxemia episodes per hour by 61% and 67% respectively, when compared with placebo (111493). Caffeine and aminophylline have similar effectiveness for management of apnea, bradycardia, and hypoxemia, but caffeine has a wider range of safe plasma levels and lower rates of tachycardia and feeding intolerance (111492).
• Postoperative headache. Oral or intravenous caffeine is approved by the US Food and Drug Administration (FDA) for preventing headache in postoperative patients who regularly consume caffeinated products. Details: Clinical research shows that using caffeine is effective for preventing postoperative headache in patients who regularly consume caffeinated products. Intravenous caffeine does not seem to be effective in non-regular caffeine consumers. Studied doses have included 200 mg intravenously or oral doses calculated based on average daily consumption (2725,2726). Caffeine is an FDA-approved product for preventing headache in postoperative patients who regularly consume caffeinated products.
• Tension headache. Oral caffeine in combination with analgesics is approved by the US Food and Drug Administration (FDA) for treating tension headache. Details: Taking caffeine orally in combination with analgesics is effective for treating simple tension headache. Taking caffeine 100 mg alone is more effective at reducing tension headache pain when compared with placebo, but less effective than the combination of caffeine and analgesics. Caffeine 130 mg has been used with acetaminophen 1000 mg or with acetaminophen 500 mg and aspirin 500 mg. Caffeine 50 mg has been used with acetylsalicylic acid 250 mg and acetaminophen 200 mg (2718,11832,37668,37773).

LIKELY EFFECTIVE

• Mental alertness. Oral caffeine increases mental alertness. However, it might not improve performance or accuracy to the same extent achieved through adequate sleep. Details: Consumption of caffeinated beverages or caffeine supplements seems to prevent a decline in alertness and cognitive capacity when consumed throughout the day (4221,4224,36439,37727,37757,37759,38070,38075,38158,91093)(91075). Caffeine appears to be especially effective in individuals that are not regular users (91074). Taking caffeine 100-600 mg can improve alertness and speed following prolonged sleep deprivation but usually does not affect mental performance or accuracy (10205,37716,37755,37806,37992,38007,38035,38139,91049,91072)(103706,112736). Drinking coffee containing caffeine 100 mg prior to a cognitive performance test improves reaction times in people with recent poor sleep quality, and in those with adequate sleep. However, the increase in vigilance occurring in the sleep-deprived people does not bring their performance up to the level seen with adequate sleep. Also, the number of errors made by sleep-deprived people seems to increase, suggesting that caffeine may have a detrimental effect on inhibitory control (98809). Caffeine also appears to reduce cognitive impairment caused by medications such as chlorpheniramine (91058). Combining caffeine with certain other supplements may improve mental performance. Taking caffeine 80 mg with taurine seems to provide a small improvement in mental performance (9899), although this effect is not observed in sleep deprived subjects (38154). Some clinical research shows that combining caffeine 40-75 mg with glucose 37.5 grams or L-theanine 97-100 mg improves mental performance better than placebo or either substance alone (13732,37762,37903,38116); however, other clinical research shows no additional benefit from combining L-theanine and caffeine (91045).

POSSIBLY EFFECTIVE

• Athletic performance. Oral caffeine taken 30-150 minutes prior to physical activity seems to modestly improve muscle strength and physical endurance, although the magnitude of effect is variable and may be dependent on a number of patient- and activity-specific factors. Caffeine in excess of 800 mg daily can result in levels greater than those allowed by the National Collegiate Athletic Association. Details: Clinical research and meta-analyses of clinical research show that taking caffeine 2-10 mg/kg modestly improves work produced, muscle strength, physical endurance, and athletic performance (10203,11832,37648,37894,38054,38063,95955,100362,100365,100371)(103701,103703,108798,111250). Meta-analyses of studies using caffeine 3-9 mg/kg as a single dose prior to endurance time trials reports variability in results. Sports studied included running, rowing, cycling, swimming, and Nordic skiing, and included both recreational and trained athletes. Overall there was a small positive effect on time to exhaustion, endurance performance, and mean power output, and a decrease in the time needed to complete the trials when compared with placebo (98808,111497). Another meta-analysis of small clinical trials shows that the benefit of caffeine on athletic performance seems to increase with increased duration of the activity. This suggests that caffeine can improve physical endurance during athletic activities (100371). In these trials, caffeine is typically provided as a single dose 30-150 minutes prior to testing (98808), although one study suggests that taking caffeine 60 minutes prior to peak activity has the most consistent ergogenic benefits (104577). Most research has investigated the acute effects of a single dose of caffeine. The evidence is mixed as to whether chronic intake of caffeine could induce tolerance and reduce any acute ergogenic benefits. One study shows that the consistent consumption of caffeine 3 mg/kg daily for 28 days eliminates the acute benefits of caffeine in work produced when compared with placebo, suggesting the development of tolerance (95955). However, chronic use of caffeine at a dose of 6 mg/kg for 4 days does not seem to induce tolerance to an acute dose of caffeine 6 mg/kg taken 60 minutes prior to a cycling time trial in males who are moderate to high users of caffeine (104576). Similarly, a small clinical study in trained individuals shows that acute supplementation with oral caffeine 6 mg/kg about 1 hour prior to performance improves strength and endurance when compared with placebo or control, regardless of habitual caffeine consumption (108804). Differences may be due to the type of exercise, the acute dose of caffeine, the length of the chronic intake period, and/or the normal caffeine intake of the athlete. Some clinical research also shows that taking caffeine can decrease subjective feelings of exertion and fatigue during exercise such as fencing and cycling (17618,37656,91026,91058,91062). Although some other clinical studies show that caffeine does not affect perceived exertion, caffeine does seem to improve performance and cause small increases in the amount of physical work done when compared with placebo in various athletes, including cyclists, runners, basketball players, and golfers (37702,37860,37872,38031,38119,38320,91037,91077,97457,97459)(104580,108800,108804). These effects do not seem to be dependent upon the dose of caffeine (97459), although some research shows that the timing of caffeine intake and exercise may alter overall benefit, with a greater effect seen in the morning compared to the evening (97457,104580). Caffeine might improve performance in some athletic activities but not others. Some research shows that caffeine does not improve performance during athletic activities requiring a high amount of exertion over a short period of time. Such activities include sprinting and lifting (11832,37564,37758,37837,37841,37890,38319,95963,97459,112740). However, it is possible that the negative lifting studies were underpowered. Ballistic exercise, such as jumping or throwing, requires rapid increases in velocity, force, and muscle activation. A meta-analysis of 10 studies shows that caffeine in a range of doses (mean: 3 mg/kg) has a significant ergogenic effect on throwing performance and velocity (111488). A meta-analysis of small studies shows that caffeine modestly improves bench press repetitions and maximum strength, but not perceived exertion, when compared with placebo. Caffeine also tends to improve these parameters for leg presses, but the improvement does not reach significance when compared with placebo (103701). A very small study in healthy males shows that taking caffeine alone, 6 mg/kg prior to bench press exercises, has a greater ergogenic benefit than a multi-ingredient supplement containing the same dose of caffeine in combination with L-tyrosine, beta-alanine, L-citrulline maleate, arginine alpha-ketoglutarate, and L-taurine (111250). A meta-analysis of small clinical studies in female team-sport athletes shows that caffeine improves specific team-sport skills but has no effect on perceived exertion or agility tests performed after exertion (108799). Conversely, a small individual clinical study shows that taking caffeine 6.5 mg/kg 60 minutes before strength training decreases perceived exertion while increasing the number of repetitions of both upper and lower limb exercises by 17% to 33% over placebo (104581). Most studies suggest that there is significant inter-individual variability in response to caffeine for improvement of athletic performance (100365). These differences might be due, at least in part, to genotype (100370), although research is conflicting. Caffeine is metabolized by the cytochrome P450 1A2 (CYP1A2) enzyme. One small clinical trial in resistance-trained males shows that taking caffeine 6 mg/kg improves resistance exercise performance in those homozygous for the CYP1A2 rs762551 polymorphism (AA) when compared with those without or heterozygous for that polymorphism (CC or A/C, respectively) (100370). However, another clinical study in trained male athletes shows that taking oral caffeine 4 mg/kg about 30 minutes prior to performance decreases handgrip strength by about 13% in individuals with the CC genotype when compared with placebo, but not in those with the AA or A/C genotypes. No groups experienced an improvement in vertical jump performance (108803). Another small clinical study suggests that CYP1A2 genotype does not affect exercise performance in athletes 60 minutes after taking caffeine 3 mg/kg. In addition, the ADORA2A genotype, which plays a role in caffeine sensitivity, does not seem to affect exercise performance benefits from caffeine (104578). However, these studies are small and further research is needed to clarify how these polymorphisms may impact the athletic performance benefits of caffeine. Limited research has also evaluated the use of a caffeine mouth rinse, with mixed findings. Two very small clinical studies in healthy trained males shows that rinsing the mouth with 25 mL of water containing caffeine 85 or 300 mg for 5-10 seconds does not affect athletic performance or time to exhaustion while cycling when compared with placebo (103709,108801). However, another small study in healthy Taekwondo athletes fasting for Ramadan suggests that using a mouth rinse containing caffeine 6 mg/kg, ten seconds prior to exertion, modestly reduces perceived exertion and modestly improves kick performance when compared with using a placebo rinse (103710). Similarly, another small clinical study in healthy, resistance-trained males shows that rinsing the mouth with 25 mL of a solution containing caffeine 3%, but not 1% or 2%, reduces perceived exertion and increases muscular endurance, but not strength, when compared with placebo. The mouth rinse was used for 5 seconds immediately prior to a strength test or once per minute for 2 minutes during a muscular endurance test (108802). Preliminary clinical research has also investigated the use of caffeine in combination with other ingredients, such as sodium bicarbonate however these studies have not demonstrated clear benefits in athletic performance over taking caffeine alone (112740).
• Bronchopulmonary dysplasia. Intravenous caffeine may reduce the risk for bronchopulmonary dysplasia in preterm infants. Details: Population research has found that initiating caffeine treatment prior to the third day of life in premature infants is associated with a reduced risk of developing bronchopulmonary dysplasia compared to later initiation of treatment with caffeine. Additionally, a meta-analysis of available clinical research shows that high-dose caffeine (40-80 mg/kg loading dose, 20 mg/kg daily maintenance) lowers the risk of bronchopulmonary dysplasia when compared with standard dosing (20 mg/kg loading dose, followed by 5-10 mg/kg daily maintenance). However, small sample sizes and high heterogeneity limit the validity of these findings (97462,100364).
• Diabetes. Dietary caffeine seems to be beneficial for the prevention of type 2 diabetes; it is unclear if it is beneficial for the prevention of gestational diabetes. Also, it is unclear if oral caffeine is beneficial in patients with type 1 or type 2 diabetes. Details: Total caffeine consumption from beverages such as coffee or tea is associated with a lower risk of developing type 2 diabetes. This effect appears to be dose-dependent (11353,14313,37850,37871,91040,100368). For example, an increase of 200 mg daily caffeine intake seems to be associated with a 14% decrease in the incidence of type 2 diabetes (91055). Additionally, in North American males, consuming caffeine 417 mg daily from coffee or tea is associated with a 20% lower risk of developing type 2 diabetes when compared with those consuming less than 37 mg daily. North American females consuming at least 258 mg of caffeine daily from coffee or tea seem to have a 10% to 30% lower risk of developing type 2 diabetes when compared with those consuming less than 140 mg daily (11353). Japanese adults who consume at least 416 mg of caffeine daily from beverages including coffee or green tea seem to have a 33% lower risk of developing type 2 diabetes compared to those who consume no more than 57 mg daily. The risk reduction appears to be more pronounced in Japanese females when compared with males (14313). It is unclear if caffeine is beneficial in adults with diabetes. A few small studies show that caffeine consumption may further reduce insulin sensitivity in patients with type 2 diabetes, gestational diabetes, or those at risk for developing diabetes (13744,37653,37820). Caffeine consumption has also been evaluated during pregnancy. An observational study has found that self-reported consumption of beverages containing up to 100 mg of caffeine at 16-22 weeks' gestation is associated with a 47% lower risk of developing gestational diabetes when compared with no intake (108814). Research regarding the effects of caffeine in patients with type 1 diabetes shows conflicting results. One study shows that taking caffeine 250 mg twice daily for 2 weeks can reduce the incidence of elevated blood sugar at night in patients with type 1 diabetes (37660). However, another study in patients with type 1 diabetes shows that taking caffeine 200 mg daily for 3 months may increase the ability to perceive hypoglycemic symptoms when compared with placebo, although overall glycemic control does not seem to be affected (6024).
• Memory. Oral caffeine seems to be beneficial for short-term memory recall in college students and extroverted personalities. It is unclear if oral caffeine is beneficial for introverted personalities or other populations. Details: Taking a single dose of caffeine 65-200 mg orally daily seems to improve memory function in some individuals such as college students and people with extroverted personalities. A small study shows that taking caffeine does not improve memory function in individuals with introverted personalities (37845,38071,91080).
• Obesity. Oral caffeine, when taken in combination with ephedrine or as a component of green tea, seems to be beneficial for weight loss, short-term. Details: Taking caffeine orally, in combination with ephedrine or as a component of green tea, seems to help reduce weight, short-term (695,696,1704,8647,16892,37617,37831). Caffeine 192 mg in combination with ephedra 20-90 mg per day for 6 months seems to cause a modest weight reduction (5.3 kg) in people with a body mass index (BMI) between 25-40 kg/m². This combination, along with limiting fat intake to 30% of calories and moderate exercise, also seems to reduce body fat, decrease low-density lipoprotein (LDL) cholesterol, and increase high-density lipoprotein (HDL) cholesterol. However, even in carefully screened and monitored otherwise healthy adults, caffeine/ephedra combinations can cause small changes in blood pressure and heart rate (8647). Preliminary clinical research also shows that taking 1000 mg of a proprietary combination product containing caffeine and multiple other ingredients (Prograde Metabolism) twice daily for 8 weeks in conjunction with dieting reduces body weight, fat mass, waist circumference, and hip circumference by 1.5%, 5%, 1.8%, and 1.3%, respectively, when compared with dieting alone (40802).
• Pain (acute). Oral caffeine, when taken in combination with acetaminophen, propyphenazone, ibuprofen, or other pain-relieving agents, seems to be beneficial for acute pain. Details: Clinical research shows that taking caffeine 50-130 mg in combination with acetaminophen, propyphenazone, ibuprofen, or other pain-relieving agents can reduce acute pain when compared with the effects of pain-relieving agents alone (37587,37904,38036,38303,91038). Adding ≥100 mg caffeine to treatment with acetaminophen or ibuprofen results in 5% to 10% more patients that achieve at least 50% of maximum pain relief for over 4 hours when compared to treatment with acetaminophen or ibuprofen alone (91038).
• Postdural puncture headache. Oral or intravenous caffeine seem to be beneficial for preventing postdural puncture headache. Details: Using caffeine 300 mg orally or 500 mg in 1,000 mL normal saline intravenously seems to help treat and prevent postdural puncture headache (2727,2728). Using a combination of ergotamine and caffeine seems to be less effective than gabapentin for treating this condition (38147). Lower doses of oral caffeine may not be beneficial. Clinical research shows that oral caffeine, 75-125 mg, does not decrease the risk of postdural headache (91022).

POSSIBLY INEFFECTIVE

• Atrial fibrillation. Oral caffeine does not seem to prevent atrial fibrillation after cardiopulmonary bypass. In addition, it might increase the risk of gastrointestinal side effects. Details: In adults undergoing surgery with cardiopulmonary bypass, taking caffeine 400 mg every 8 hours for 6 doses does not seem to reduce the risk of developing atrial fibrillation during the first three post-operative days. This clinical study was stopped prior to the completion of recruitment after an interim analysis showed increased incidence of postoperative nausea and vomiting, and no effect on the incidence of atrial fibrillation (97451).
• Attention deficit-hyperactivity disorder (ADHD). Oral caffeine does not seem to reduce symptoms of ADHD in children. Details: Most research suggests caffeine does not significantly reduce ADHD symptoms in children when used at tolerable doses (10755,10756,10757,10758,10759,10760). The use of caffeine in adolescents and adults with ADHD has not been studied.

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Age-related cognitive decline. It is unclear if oral caffeine prevents cognitive decline with aging. Details: Population research from a small cohort of elderly females shows that caffeine intake of more than 371 mg daily is associated with an attenuation in cognitive decline when compared to less than 30 mg daily. This is equivalent to the difference seen over a 7 year span of age. Caffeinated coffee consumption, but not caffeinated chocolate, tea, or cola, was associated with this attenuation in cognitive decline (91088).
• Alzheimer disease. It is unclear if oral caffeine is beneficial for preventing dementia; the available research is conflicting. Details: Population research from the UK Biobank has found that caffeine intake up to 400 mg daily is associated with a 24% to 34% reduced risk of developing Alzheimer disease when compared with lower intake. Conversely, population research from the Rush Memory and Aging Project in the US has found that caffeine intake of more than 100 mg daily is associated with a 41% increased risk of developing Alzheimer disease when compared with lower intake. However, when those with mild cognitive impairment at baseline or cases diagnosed within 2 years of follow-up are excluded, these findings become insignificant (108810).
• Asthma. Oral caffeine seems to modestly improve airway function for up to 4 hours in patients with mild to moderate asthma. However, it is unclear if oral caffeine has a clinically significant effect on asthma symptoms or quality of life. Details: Taking caffeine 9 mg/kg orally appears to modestly improve airway function for up to 4 hours in people with mild to moderate asthma (37907,37915). However, more research is needed to determine the appropriate dose, whether any benefit is clinically significant, or whether tolerance occurs with chronic dosing.
• Cancer pain. It is unclear if intravenous caffeine is beneficial for cancer pain. Details: Clinical research shows that receiving caffeine 200 mg intravenously once daily for 2 days results in a significant reduction in pain intensity by 0.833 points on the NRS scale when compared with control in patients receiving opioids for pain from advanced cancer (91081).
• Cognitive function. It is unclear if oral caffeine improves cognitive performance in trained athletes. Details: A meta-analysis of small studies in trained adult athletes shows that consumption of a low to moderate amount of caffeine 15-60 minutes prior to exercise and during exercise improves attention performance, but not reaction time or inhibitory control, when compared with placebo (108797). The validity of these findings is limited by unclear reporting.
• Dementia. It is unclear if oral caffeine is beneficial for preventing dementia or improving behavior in patients with dementia. Details: Population research from the Women's Health Initiative has found that caffeine intake of more than 175 mg daily is associated with a 26% reduced risk of developing probable dementia or global cognitive impairment when compared to less than 175 mg daily in postmenopausal adults 65-80 years of age (97458). Population research from the UK Biobank has found that caffeine intake up to 400 mg daily is associated with a 17% to 26% reduced risk for developing all-cause dementia when compared with lower intake. Conversely, population research from the Rush Memory and Aging Project in the US has found that caffeine intake of more than 100 mg daily is associated with a 35% increased risk of developing all-cause dementia when compared with lower intake. However, when those with mild cognitive impairment at baseline or cases diagnosed within 2 years of follow-up are excluded, these findings become insignificant (108810). Caffeine consumption has also been evaluated in patients with dementia. A cross-sectional study in patients with dementia in a care home has found that intake of 'normal' to 'high' amounts of caffeine are associated with reduced agitation and other behavioral symptoms when compared to 'low' intakes of caffeine (104574).
• Depression. It is unclear if oral caffeine is beneficial for depression prevention. Details: Some population research found that caffeine intake is associated with an increased incidence of depressive symptoms in pediatric patients (37839,38162). However, other population research found that caffeinated beverage intake is associated with a decreased incidence of depression in adults (37969,38165,91067,100366).
• Electroconvulsive therapy (ECT) augmentation. Although there has been interest in using intravenous caffeine sodium benzoate to augment electroconvulsive therapy, there is insufficient reliable information about the clinical effects of caffeine for this condition.
• Exercise-induced hypoxemia. It is unclear if oral caffeine is beneficial for hypoxemia associated with exercise. Details: Preliminary clinical research in athletes experiencing exercise-induced hypoxemia shows that taking caffeine 8 mg/kg can improve exercise ventilation, but not ventilatory response or oxygen saturation, when compared with placebo (37750).
• Exercise-induced muscle soreness. It is unclear if oral caffeine is beneficial for reducing muscle soreness during exercise. Details: There is conflicting clinical evidence as to whether caffeine can reduce exercise-induced muscle pain. Some evidence shows that taking caffeine 100 mg or 10 mg/kg can reduce muscle pain during exercise when compared with placebo (37622,38146). However, the effect of lower doses is unclear. Some evidence shows that taking caffeine 5 mg/kg may reduce exercise-induced muscle pain when compared with placebo (37747,91050), while other evidence suggests that taking caffeine 2-5 mg/kg does not affect muscle pain during exercise (38141).
• Gallbladder disease. It is unclear if increased dietary caffeine intake reduces the risk of developing gallstones. Details: Consumption of caffeinated beverages that provide 400 mg or greater of caffeine per day is associated with a significantly reduced risk of developing symptomatic gallstone disease (3345,8032). The effect seems to be dose-dependent; consumption of 800 mg caffeine per day has the greatest reduction in risk (3345).
• Hepatitis C. It is unclear if increased dietary caffeine reduces the risk for hepatitis C-associated severe liver inflammation, although it may reduce the risk of developing advanced fibrosis. Details: A meta-analysis of population research has found that regular consumption of caffeine at doses of at least 123 mg daily is associated with a 48% reduced risk of advanced liver fibrosis when compared to lower caffeine intake in patients with hepatitis C virus (95947). An individual population study also found that higher intake of caffeine from coffee is associated with reduced severity of liver fibrosis in patients with chronic hepatitis C virus. For these patients, the risk of advanced fibrosis is reduced by 14% for each 67 mg of caffeine (37896). However, caffeine intake does not appear to be associated with a reduced risk of moderate to severe liver inflammation in patients with hepatitis C (95947).
• Hypnic headache. It is unclear if oral caffeine reduces the pain associated with this rare condition. Details: Anecdotal evidence suggests that drinking a cup of coffee containing caffeine before bed or upon waking up may help alleviate pain associated with hypnic headaches (38078).
• Hypotension. It is unclear if oral caffeine is beneficial in people with low blood pressure. Details: Preliminary clinical research shows that consuming caffeinated beverages increase blood pressure in elderly people with postprandial hypotension (11834,11835).
• Intermittent claudication. It is unclear if oral caffeine is beneficial for intermittent claudication. Details: Taking a single dose of caffeine 6 mg/kg orally seems to improve walking distance, muscular strength, and endurance in patients with intermittent claudication; however, balance seems to be reduced (38038).
• Liver disease. It is unclear if oral caffeine is beneficial for liver disease prevention. Details: Population research found that there is an inverse association between intake of coffee and the incidence of liver cirrhosis (37576,37608). However, it is unclear if this effect of coffee is attributable to caffeine, since other caffeinated beverages do not show this effect.
• Narcolepsy. It is unclear if oral caffeine is beneficial for narcolepsy. Details: A small clinical study in patients with narcolepsy shows that taking caffeine 200 mg daily in the morning for 1 week does not affect reaction time, but modestly reduces drowsiness, when compared with baseline (103698). The validity of this finding is limited by the lack of a statistical comparison between the treatment and placebo groups.
• Neonatal resuscitation. It is unclear if oral caffeine improves the likelihood for successful extubation in preterm infants. Details: Preliminary clinical research in extremely preterm infants requiring mechanical ventilation within the first 5 days of birth shows that early administration of caffeine, given as a loading dose of caffeine citrate 20 mg/kg followed by a maintenance dose of 5 mg/kg daily until extubation, does not reduce mortality or shorten time to first successful extubation when compared to giving a bolus dose of caffeine citrate 20 mg/kg just prior to extubation (97461).
• Nocturnal enuresis. Reducing caffeine intake might reduce the frequency of nocturnal enuresis episodes in children. Details: Preliminary clinical research in children aged 6-15 years with primary nocturnal enuresis shows that limiting caffeine intake to less than 30 mg daily reduces the mean number of bedwetting episodes from 3.5 to 2.4 per week, when compared with no change in the group with intakes of 80-100 mg daily. The probability of bedwetting in the caffeine restricted group was about 14% lower than that in the control group (111495).
• Nonmelanoma skin cancer. It is unclear if oral caffeine is beneficial for nonmelanoma skin cancer prevention. Details: A review of available population research shows that increased caffeine intake from any source is associated with a 14% reduction in the risk of developing nonmelanoma skin cancer. Consumption of caffeinated coffee, but not decaffeinated coffee, is associated with an 18% reduced risk (97465).
• Parkinson disease. Although consuming caffeinated beverages might reduce the risk of developing Parkinson disease, it is unclear if oral caffeine is beneficial for improving symptoms. Also, oral caffeine does not seem to prevent tardive dyskinesia. Details: It is unclear whether caffeine improves some symptoms of Parkinson disease, as results from clinical research are conflicting (91069,95951,95954,103705). One clinical study in Parkinson disease patients with extreme daytime somnolence shows that taking caffeine 100 mg twice daily for 3 weeks and then 200 mg twice daily for 3 weeks results in modest improvements in rigidity and bradykinesia, but inconsistent improvements in drowsiness, when compared with placebo (91069). Other clinical research shows that caffeine 200 mg twice daily does not lead to improvements in motor severity, cognition, or somnolence after 6, 12, or 18 months when compared with placebo (95954). Furthermore, a large retrospective study has found that caffeine consumption of more than 300 mg daily for 18 months in conjunction with dopaminergic therapy does not slow the rate of Parkinson disease progression. This research also shows that a reported consumption of caffeine greater than 300 mg, in conjunction with creatine 10 grams daily for 18 months, may accelerate the rate of Parkinson disease progression (95951). The retrospective nature of this study limits the validity of these findings. Caffeine does not appear to be helpful for reducing the risk of tardive dyskinesia. A retrospective analysis has found no definitive difference in onset of tardive dyskinesia in Parkinson patients consuming more than 204 mg caffeine daily when compared with those consuming less than 68 mg daily (91090). Despite these mainly negative findings, large-scale epidemiological studies have found that people who consume caffeinated beverages, such as coffee, tea, and cola, have a decreased risk of Parkinson disease (37931,91060,91071,103705). Males consuming 3-4 cups (28 oz) of caffeinated coffee per day, or 421-2716 mg total caffeine, seem to have the lowest risk of developing this condition. However, a lower risk is also associated with consumption of as little as 124-208 mg of caffeine (6022). In females, more moderate caffeinated coffee consumption, such as 1-3 cups per day, seems to be best (1238). Caffeine does not appear to provide additional protection from Parkinson disease in cigarette smokers (9236,91060).
• Postoperative ileus. It is unclear if oral caffeine is beneficial for improving bowel recovery following colorectal resection. Details: A small clinical study in adults undergoing elective laparoscopic colon or rectal resection with primary anastomosis shows that caffeine citrate 100 mg three times daily, starting on the morning of postoperative day 1, reduces the time to self-reported first bowel movement by about 18 hours when compared with placebo. There was no difference between groups in time to self-reported first flatus (108808). Another small study in adults undergoing elective laparoscopic colectomy shows that taking caffeine 100 mg or 200 mg three times daily does not reduce the mean time to first bowel movement, colonic transit time, or length of hospital stay when compared with placebo (111484). However, a meta-analysis of these two clinical trials shows that taking caffeine does not decrease the time to the first stool or length of hospital stay when compared with control (112732).
• Postoperative pain. It is unclear if intravenous caffeine is beneficial for reducing opioid consumption in adults undergoing surgery. Details: A small clinical study in adults undergoing laparoscopic colorectal and gastrointestinal surgery shows that intravenous caffeine citrate 200 mg at the initiation of surgical closure has no effect on cumulative opioid consumption through postoperative day 3 when compared with placebo. In fact, post-hoc analysis with adjustment for age, sex, comorbidities, history of anxiety or depression, and open surgical conversion suggests an increase in opioid consumption with administration of caffeine when compared with placebo (108809).
• Pre-eclampsia. It is unclear if oral caffeine intake affects the risk of gestational hypertension or pre-eclampsia. Details: a meta-analysis of 10 observational studies including about 115,000 pregnant people did not find an association between the level of caffeine intake during pregnancy and the risk of developing gestational hypertension or pre-eclampsia (111485).
• Stroke. It is unclear if oral caffeine is beneficial for stroke prevention. Details: Population research has found that increased intake of either caffeinated or decaffeinated coffee is associated with a decreased risk of stroke in females (37804). However, it is not clear if the effect of coffee is attributable to the caffeine component.
• Tinnitus. It is unclear if oral caffeine is beneficial in patients with chronic tinnitus. Details: A small clinical study in adults with chronic tinnitus shows that taking a single dose of caffeine 300 mg improves mood and quality of life at 1 hour when compared with baseline. (108805). The lack of statistical comparison to the placebo group limits the validity of these findings. More evidence is needed to rate the effectiveness of caffeine for these uses.

(Read more about CAFFEINE)

LIKELY EFFECTIVE

• Diabetic neuropathy. Applying a specific prescription patch containing capsaicin 8% or a specific cream containing capsaicin 0.075% can reduce pain in diabetic neuropathy. Details: Clinical research has evaluated the use of a specific patch (Qutenza, NeurogesX Inc.) containing capsaicin 8%, which is approved as a prescription medication by the US Food and Drug Administration (FDA) for the treatment of diabetic peripheral neuropathy. The research in this population shows that a single application of the patch on the painful parts of the feet for 30-90 minutes following pretreatment with topical anesthetics reduces pain for up to 12 weeks when compared with placebo (40719,96453). Patients using the patch experience reduced sleep interference and an average 28% reduction in pain, compared with a 21% reduction with placebo. Additionally, 50% of patients receiving the patch experience pain relief within 19 days, compared to 72 days for those receiving placebo (96453). A meta-analysis of the available clinical research for diabetic peripheral neuropathy found that one-time application of this patch is equally effective to duloxetine 20-120 mg daily, pregabalin 75-600 mg daily, and gabapentin 300-3600 mg daily in producing a 30% or 50% pain reduction. The dose of oral medication used in the evaluated studies did not impact the comparative efficacy of the capsaicin patch (96450). Other clinical research shows that applying cream containing capsaicin 0.075% four times daily for 8 weeks reduces pain intensity when compared with placebo in patients with diabetic peripheral neuropathy (40547,40592,40607). A meta-analysis of clinical research shows that applying cream containing capsaicin 0.075% reduces pain similarly to 5% lidocaine-medicated plaster (40674). Topical cream containing capsaicin 0.075% (Zostrix-HP, Link Medical Products Pty Ltd.) is FDA-approved as an over-the-counter (OTC) medication for this indication (272). However, applying a capsaicin lotion less frequently or with a lower concentration of capsaicin does not seem to be beneficial. A small clinical study in patients with diabetic neuropathy shows that applying a specific lotion (Capsika-75 lotion, Bangkok Drug Company) containing capsaicin 0.075% three times daily for 8 weeks improves pain to a similar degree as a placebo lotion (102277). This study was limited by a high dropout rate, high placebo effect, and poor adherence to therapy. Furthermore, cream or gel (such as Capsika-25 gel, Bangkok Drug Company) containing lower amounts of capsaicin do not appear to be effective for reducing diabetic peripheral neuropathy pain (92984).
• Pain (chronic). Topical cream containing capsaicin can reduce chronic pain associated with various conditions. Topical capsaicin is FDA-approved for this use. Details: Several clinical studies show that topically applying cream containing capsaicin, the active capsicum constituent, 0.05% to 0.075% temporarily relieves chronic pain from rheumatoid arthritis, osteoarthritis, back pain, jaw pain, psoriasis, and neuropathic conditions (12401,17701). Capsaicin, used in topical preparations, is FDA-approved for these uses (272). It can take up to 14 days for the full analgesic effect. For neuropathic pain, the number needed to treat using capsaicin 0.075% for eight weeks is 5.7 (12401). For musculoskeletal pain, for every 8.1 patients treated with capsaicin 0.025%, 1 patient would achieve at least a 50% reduction in pain (12401). Also, applying capsaicin 0.05% (Finalgon CPD Warmecreme) three times daily for 21 days seems to cause a 49% reduction in chronic soft tissue pain when compared with placebo (17701).
• Postherpetic neuralgia. Applying a specific prescription patch containing capsaicin can reduce postherpetic neuralgia pain, especially in patients with the lowest pain scores. Details: Clinical research has evaluated the use of a specific patch (Qutenza, NeurogesX Inc.) containing capsaicin 8%, which is approved as a prescription medication by the US Food and Drug Administration (FDA) for the treatment of postherpetic neuralgia. Research in this population shows that applying a single patch for 60-90 minutes reduces average pain over 24 hours by 27% to 37% for up to 12 weeks, compared to only 4.4% to 26% in patients in the control group (40659,40679,40686,40691,40719,40728,40800,92985,96451,96452). The number needed to treat to achieve at least a 30% or 50% reduction in pain intensity is 10 and 12, respectively; the number needed to treat to achieve an additional beneficial outcome over placebo at 8 weeks and 12 weeks is 9 and 7, respectively (40800,96451). The pain reduction with this patch has an onset of a few days after treatment and the effect lasts for about 5 months (92986). However, some evidence shows that the reduction in pain is only significant for patients who have had postherpetic neuralgia for at least 6 months (40686). Additionally, the reduction in pain and duration of response appears to be greatest for patients with lower pain scores and low sensitivity to light touch at baseline, as well as patients not using concomitant systemic neuropathic pain medications, whereas patients with high pain scores, high sensitivity to touch, or those using systemic neuropathic pain medications experience the smallest and least sustained reduction in pain (40728,96458). Also, other evidence suggests that this patch may be less effective at relieving postherpetic neuralgia when compared with 5% lidocaine-medicated plaster (40688).

POSSIBLY EFFECTIVE

• Back pain. Topical capsicum or capsaicin seems to be beneficial for reducing back pain. Details: A meta-analysis of generally low-quality clinical research, as well as individual studies, show that applying a capsicum-containing plaster providing 11 mg of capsaicin per plaster or 22 mcg of capsaicin per square centimeter of plaster to the back once daily in the morning for 4-8 hours reduces low back pain when compared with placebo (15259,15260,15261). Applying capsaicin 0.05% (Finalgon CPD Warmecreme) three times daily for 21 days seems to cause a 58% reduction in low back pain when compared with placebo (17701). Also, in a mixed group of patients with acute back or neck pain, a large clinical trial shows that four topical applications with a gel containing capsaicin 0.075% with diclofenac 2% every 12 hours modestly reduces pain on motion when compared with diclofenac alone or placebo. The number of patients with at least a 50% reduction in pain from baseline was modestly higher. Capsaicin 0.075% was similarly effective alone and when combined with diclofenac 2% (105202). However, only about half of the patients in this study had back pain.
• Cluster headache. Intranasal capsaicin seems to be beneficial for preventing cluster headaches. Its effect in the treatment of cluster headache is unclear. Details: Some clinical research shows that using the capsicum constituent capsaicin intranasally reduces the frequency of episodic or chronic cluster headache attacks (14323,14351,14352,14358). Capsaicin suspensions of 0.1 mL of a 10 mM suspension, providing 300 mcg/day of capsaicin, has been applied to the ipsilateral nostril. Applications are continued once daily until a burning sensation is no longer experienced (14351,14358). Intranasal application of capsaicin 0.025% (Zostrix, Rodlen Laboratories) might also decrease symptom severity during an acute cluster headache attack. Clinical research shows that daily treatment for 7 days decreases symptom severity over the following week (14353). Ipsilateral, or same side, nostril application of capsaicin appears to be more effective than contralateral application (14351). Due to severe pain associated with intranasal capsaicin administration, pretreatment with intranasal local anesthetic is usually used.
• Nonallergic rhinitis. Intranasal capsaicin in a dose of at least 0.1 mM seems to improve symptoms of nonallergic rhinitis. It is unclear if lower doses of capsaicin are beneficial. Details: Clinical research shows that repeated intranasal in-clinic treatments with capsaicin, the active capsicum constituent, or with capsicum oleoresin, over a period of one to three days, can significantly decrease symptoms of non-allergic, non-infectious perennial rhinitis symptoms (14328,14357,15016,40595,105204,105205). A decrease of symptoms has been observed for up to 6-9 months following these treatments (14328,14357). The following doses have been used: capsaicin 0.15 mg per dose for up to 7 doses over a 14-day period (14328), capsaicin 0.0033 mol once weekly for 5 weeks (14357), capsaicin 15 mcg/0.1 mL applied three times daily for 3 days (15016), and capsaicin 1-4 mcg per puff, applied 3 times in each nostril daily for 3 days (40595). Due to severe pain associated with intranasal capsaicin administration, pretreatment with intranasal local anesthetic is usually used. Personal use of an intranasal spray with a lower dose of capsaicin might also be effective. Clinical research shows that two 0.4 mL puffs with an intranasal spray in each nostril daily for 4 weeks providing capsaicin 0.01 mM, but not 0.001 mM, is more effective than placebo for reducing symptoms of idiopathic rhinitis. This benefit is maintained for an additional 8 weeks. This protocol was at least as effective as receiving five repeated hourly intranasal spray treatments in hospital with capsaicin 0.1 mM (105204).
• Osteoarthritis. The American College of Rheumatology (ACR) conditionally recommends topical capsaicin for knee osteoarthritis, but not for hip or hand osteoarthritis. Details: A meta-analysis of 4 preliminary clinical trials shows that using topical capsaicin 0.025% four times daily has modest benefit for osteoarthritis when compared with placebo. Using capsaicin 0.0125% doesn't seem to be effective (102408). The American College of Rheumatology (ACR) conditionally recommends topical capsaicin for knee osteoarthritis. However, it does not recommend its use for hip osteoarthritis due to the depth of the joint beneath the skin surface, nor for hand osteoarthritis, due to the risk for contamination of the eye (102114).
• Pain (acute). Topical capsicum seems to be beneficial for reducing acute pain due to trauma. Details: Clinical research in patients with trauma-related acute pain shows that topical application with a gel (Sanli Gel) containing capsaicin 0.05% three times daily for 3 days reduces pain by at least 50% in 87% of patients, compared with 63% of those using a piroxicam gel 0.5% (Felden). There was also a significantly greater number of patients with a final pain score of 4 or less. In the capsaicin group, only 12% of patients did not achieve either of these endpoints, compared with 31% in the group receiving piroxicam (105197).
• Postoperative nausea and vomiting (PONV). Applying topical capsicum to acupoints seems to be beneficial for preventing PONV. Details: Clinical research shows that applying a capsicum-containing plaster to acupoints on the hand and forearm 30 minutes prior to anesthesia and leaving in place for 6-8 hours daily for up to 3 days after surgery reduces the incidence of PONV by about 29% to 36% when compared to control (40405,40483,40610). Plasters used in these studies included Sinsin PAS (Sinsin Pharm Co.), which is standardized to contain capsicum 345.8 mg and capsicum tincture 34.58 mg per sheet (40405,40610); and Johnson's Perforated Capsicum Plaster (Johnson & Johnson Ltd.), which is standardized to contain capsicum oleoresin 1% w/w (40483).
• Postoperative pain. Applying topical capsicum-containing plaster to acupoints seems to be beneficial for reducing postoperative pain. It is unclear if a capsicum patch or capsaicin instillation prior to wound closure is beneficial for reducing postoperative pain. Details: Some clinical research shows that applying a capsicum-containing plaster to acupoints on the hands or near the knees of adults or children 30 minutes prior to anesthesia, and leaving in place for 6-8 hours daily for up to 3 days after surgery, reduces the amount of rescue analgesics needed by 29% to 39% within the first 24 hours and by 16% to 19% within the first 48 hours when compared to control (40405,40483,40520,40524,40610). The capsicum-containing plaster used in these studies (Sinsin PAS, Sinsin Pharm Co.) is standardized to contain capsicum 345.8 mg and capsicum tincture 34.58 mg per sheet (40520,40610). Other preliminary clinical research shows that applying a single patch containing the capsicum constituent capsaicin 8% (Qutenza, NeurogesX Inc.) for 30-60 minutes leads to an improvement in overall health status and an average 22% reduction in pain that lasts up to 12 weeks in patients with postoperative and posttraumatic neuropathic pain. Patches were applied to various parts of the body, including the legs, torso, feet, hands, arms, head, and neck, and the reduction in pain continued with the use of a second and third patch application. The validity of these findings is limited by the lack of a control group (96452). Other clinical evidence suggests that instilling capsaicin 15 mg during surgery immediately prior to wound closure reduces the need for pain medication for up to 2 weeks postoperatively when compared with placebo (40741).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Allergic rhinitis (hay fever). It is unclear if intranasal capsaicin is beneficial for preventing allergic rhinitis symptoms. Details: Preliminary clinical research shows that intranasal treatment with cotton wads soaked in the active capsicum constituent capsaicin 30 mcM, applied for 15 minutes and repeated over two days, reduces the severity of experimentally-induced allergic rhinitis. The severity of symptoms seems to be reduced for up to 2 months after treatment (14324). However, contradictory research shows that patients with allergic rhinitis caused by house dust mites do not have significantly improved symptoms after using a capsaicin solution providing 0.15 mg/dose for up to 7 doses over a 14-day period when compared with placebo (14360).
• Amyotrophic lateral sclerosis (ALS, Lou Gehrig's disease). Although there is interest in using oral capsicum for ALS, there is insufficient reliable information about the clinical effects of capsicum for this condition.
• Athletic performance. It is unclear if oral capsaicin is beneficial for improving athletic performance; the available research is limited to small, conflicting studies. Details: Several small clinical studies in physically active young adults show that taking capsaicin might improve some measures of athletic performance, but results are mixed overall (99409,99410,102276,105191,105198,105200). A meta-analysis of these and several other small clinical studies shows that taking the capsicum constituents capsaicin or capsiate 45 minutes before exercise improves measures of muscular endurance but does not improve aerobic endurance when compared with placebo. Doses of the capsicum constituents ranged from 1.2-24 mg, with most studies assessing a single 12 mg dose (111515). The included studies have a number of methodological problems that limit the validity of the findings, such as a small sample size, short study duration, and insufficient blinding. Also, most of the study participants were male. Other small clinical studies not included in the meta-analysis also show conflicting results. One small clinical study in untrained young adults undergoing resistance training shows that taking capsiate, a capsaicin analog, 6 mg orally twice daily for 6 weeks improves upper body, but not lower body, weightlifting performance when compared with placebo (109024). However, another small clinical trial in experienced male athletes shows that taking cayenne (GNC Nature's Fingerprint Cayenne Herbal Supplement) 3 grams, providing capsaicin 25.8 mg, daily for 7 days does not improve sprint time, rate of perceived exertion, or muscle soreness over three days when compared with placebo (105206). Capsicum has also been evaluated in combination with other ingredients. One small clinical study in untrained males shows that taking a supplement containing capsicum extract 66.7 mg, caffeine 400 mg, black pepper extract 10 mg, and niacin 40 mg prior to exercising does not improve strength, time to exhaustion, or maximal oxygen consumption when compared with placebo (37873).
• Burning mouth syndrome. It is unclear if applying topical capsaicin in the mouth is beneficial for burning mouth syndrome. Details: Preliminary clinical studies show that using 15 mL of a mouth rinse containing the active capsicum constituent capsaicin 0.02% for 30 seconds daily for 7-21 days modestly decreases burning discomfort when compared to baseline in patients with burning mouth syndrome (92991,105195). Other preliminary clinical research shows that applying 0.5 mL of a gel containing capsaicin 0.01% or 0.025% to the tongue three times daily for 14 days modestly reduces pain when compared to baseline in patients with burning mouth syndrome. The gel is spread with a cotton swab, and no food or drink is consumed for 30 minutes after application (96456). The validity of these findings is limited by the lack of a control group, the small number of patients, and occasionally unclear statistical comparisons.
• Cancer. It is unclear if eating more chili is beneficial for preventing mortality due to cancer. Details: Population research has found that consuming chili more than four times weekly is not associated with a reduced odds of cancer mortality (105208). Also, other population research has found that any consumption of hot red chili peppers is not associated with a reduced odds of mortality related to cancer (105210).
• Cannabinoid hyperemesis syndrome (CHS). Preliminary clinical research suggests that topical capsaicin might be beneficial for reducing symptoms of CHS. Details: One small clinical study in adults presenting to an emergency department (ED) with CHS shows that applying 5 grams of a cream containing capsaicin 0.1% to the abdomen modestly reduces nausea severity at 60 minutes, but not 30 minutes, when compared with a placebo cream. Nausea was completely resolved in 29% of patients, compared with 0% of those using the placebo cream. However, there was no difference in vomiting at 30 or 120 minutes (105193). This study may not have been adequately powered to detect a difference in some of these outcomes. A meta-analysis of two small, low-quality studies involving the topical use of capsaicin on the abdomen, chest, and possibly back, shows that the mean time to resolution of symptoms was 326 minutes and the mean length of stay in the emergency department was 379 minutes. However, it is unclear how these times compare to the use of placebo or standard antiemetics. This study also conducted a systematic review of the available literature, which indicates that the creams most commonly used in research provide 0.025% to 0.1% capsaicin (105201). Two low-quality, retrospective reviews also suggest that capsaicin cream may be beneficial for CHS. A retrospective review of patients in the ED with CHS has found that applying capsaicin cream 0.025% is associated with a 39% shorter time to discharge when compared with control. Patients treated with capsaicin also required fewer additional rescue treatments when compared with control (109021). Another retrospective review of patients in the ED with CHS also suggests that capsaicin cream 0.025% modestly reduces abdominal pain when compared with baseline. However, 47% and 28% of patients, respectively, received additional antiemetics or an opioid after the use of the cream (105345).
• Cardiovascular disease (CVD). It is unclear if eating more chili is beneficial for preventing mortality due to CVD. Details: Population research has found that consuming chili more than four times weekly is associated with a 34% reduced odds of CVD mortality when compared with never or rarely consuming chili, as well as 44% and 61% reduced odds of ischemic heart disease and cerebrovascular death, respectively (105208). Other population research has found that consumption of hot red chili peppers is not associated with a reduced odds of mortality related to CVD when compared with not eating hot red chili peppers (105210).
• Diabetes. It is unclear if oral capsaicin is beneficial for gestational diabetes. Details: Preliminary clinical research shows that taking chili powder containing capsaicin 5 mg daily for 4 weeks modestly reduces total cholesterol levels and reduces postprandial blood glucose levels by an average of 36 mg/dL and postprandial insulin levels by an average of 14 IU/L in patients with gestational diabetes. Compared to a placebo group, these changes are significant. However, capsaicin intake does not alter fasting plasma glucose or insulin levels (96457).
• Dry skin. It is unclear if oral capsicum is beneficial for dry skin. Details: Preliminary clinical research in adult females with low skin moisture shows that taking paprika oil extract 400 mg, standardized to include 9 mg of xanthophyll, orally daily for 4 weeks improves skin moisture and viscoelasticity scores, but not the number of wrinkles, when compared with control (109026).
• Dyslipidemia. It is unclear if oral capsicum is beneficial for reducing lipid levels. Details: A meta-analysis of three or four mainly small clinical trials in healthy adults shows that taking capsicum does not improve levels of triglycerides, total cholesterol, or high-density lipoprotein (HDL) cholesterol when compared with no treatment or placebo. However, there was a small to moderate effect on levels of low-density lipoprotein (LDL) cholesterol. Freshly chopped chili or fermented red pepper were studied for 4 and 12 weeks, respectively (105194). It is unclear if capsicum can lower lipid levels in patients with dyslipidemia or hyperlipidemia.
• Dyspepsia. It is unclear if oral capsicum is beneficial for dyspepsia. Details: Preliminary clinical research shows that taking red pepper powder 2.5 grams daily in three divided doses for 5 weeks reduces symptoms of functional dyspepsia when compared with placebo. However, in some patients, there seems to be a worsening of symptoms prior to any improvement (12410).
• Fibromyalgia. It is unclear if oral capsicum is beneficial for fibromyalgia. Details: Preliminary clinical research shows that applying cream containing the active capsicum constituent capsaicin 0.025% four times daily to tender points for 4 weeks reduces localized tenderness in patients with fibromyalgia (7038). Other preliminary clinical research shows that applying capsaicin 0.075% cream (Sensedol) three times daily to tender points for 6 weeks in addition to standard therapy increases the pain threshold when compared with standard therapy in patients with severe fibromyalgia (92979). However, capsaicin does not appear to reduce overall pain or improve physical function in patients with fibromyalgia (7038,92979). Also, the long-term effects of capsaicin on fibromyalgia-related pain are unclear.
• Gastroesophageal reflux disease (GERD). Although there is interest in using oral capsicum for GERD, there is insufficient reliable information about the clinical effects of capsicum for this condition.
• HIV/AIDS-related peripheral neuropathy. It is unclear if topical capsaicin is beneficial for this condition. Details: There is conflicting evidence regarding the effects of Qutenza (NeurogesX Inc.), which contains the active constituent of capsicum, capsaicin 8%. Although some research shows it reduces pain in patients with HIV and peripheral neuropathy (22395), other research shows no significant benefit (40746). A meta-analysis of results from both of these studies shows that applying a single capsaicin 8% patch for 30-90 minutes reduces pain intensity by at least 30% in about 30% more patients when compared to control (40800). Additional meta-analyses of the results from these two studies suggests that pain reduction with capsaicin begins a few days after treatment and lasts for about 5 months, with a number needed to treat of 11 to achieve at least a 30% reduction in pain intensity (92986,96451). Reduction in pain and duration of response appears to be greatest for females with lower pain scores at baseline, whereas males with high pain scores at baseline experience the smallest and least sustained reduction in pain (96458). Some research has also evaluated topical capsaicin 0.075%. One small clinical study shows that applying this cream does not relieve symptoms of HIV-associated peripheral neuropathy when compared with placebo (3891).
• Hypertension. It is unclear if oral capsicum is beneficial for lowering blood pressure. Details: Two meta-analyses of small clinical trials show that taking capsicum as freshly chopped chili, fermented red pepper, red pepper capsules, or capsinoid capsules orally daily for 4-12 weeks does not reduce systolic or diastolic blood pressure when compared with control. However, most subjects included in these clinical trials did not have hypertension (105194,109025).
• Intermetatarsal neuroma. It is unclear if injecting capsaicin into the third intermetatarsal space is beneficial for intermetatarsal neuroma. Details: Clinical research in adults with intermetatarsal neuroma shows that a single injection of capsaicin 0.1 mg into the third intermetatarsal space 5 minutes after administration of 2 mL of lidocaine 2% with epinephrine leads to a modest reduction in pain at weeks 1 and 4, but not weeks 2 and 3, when compared with placebo. Capsaicin also reduces the extent to which pain interferes with walking and mood, but not with work, sleep, relationships, or general activity (96454).
• Irritable bowel syndrome (IBS). It is unclear if oral capsicum is beneficial for IBS. Details: Preliminary clinical research shows that taking ground guajillo chili 1 gram, containing capsaicin 0.112%, with each meal for 7 days does not reduce symptoms of IBS (12403). A small clinical study shows that taking chili (Nguan Soon Co., Ltd.) 2.1 grams, providing 2.5 mg capsaicin, daily before meals for 6 weeks does not improve abdominal burning, fecal urgency, or abdominal pain or bloating after a spicy meal. However, there was a modest reduction in abdominal burning after a spicy meal (105207). This study may not have been adequately powered to detect a difference in some of these outcomes.
• Laryngitis. Although there is interest in gargling with capsicum for laryngitis, there is insufficient reliable information about the clinical effects of capsicum for this condition.
• Motion sickness. Although there is interest in oral capsicum for motion sickness, there is insufficient reliable information about the clinical effects of capsicum for this condition.
• Myofascial pain syndrome. It is unclear if topical capsaicin is beneficial for myofascial pain syndrome. Details: Preliminary clinical research shows that applying a specific capsaicin cream (Dipental Cream, Dalim BioTech) containing capsaicin 0.25 mg/gram along with a ketoprofen 30 mg patch (KetotopVRPlaster, Pacific Pharma) to the trapezius does not reduce pain when compared with a ketoprofen patch alone in patients with myofascial pain (92983).
• Neck pain. It is unclear if topical capsaicin is beneficial for neck pain. Details: In a group of patients with acute back or neck pain, a large clinical trial shows that four topical applications with a gel containing capsaicin 0.075% with diclofenac 2% every 12 hours modestly reduces pain on motion when compared with diclofenac alone or placebo. The number of patients with at least a 50% reduction in pain from baseline was modestly higher. Capsaicin 0.075% was similarly effective alone or when combined with diclofenac 2% (105202). However, only about half of the patients in this study had neck pain.
• Neuropathic pain. It is unclear if topical capsicum is beneficial for neuropathic pain. Details: A very small study in adults with neuropathic pain secondary to spinal cord injury shows that applying a patch containing the capsicum constituent capsaicin 8% for 60 minutes daily to the affected area for 12 weeks reduces pain at weeks 2 and 4 and improves mobility, but not quality of life, for up to 12 weeks when compared with placebo (111517). The validity of these findings is limited by insufficient blinding and the small sample size.
• Obesity. It is unclear if oral capsicum is beneficial for obesity. Details: A meta-analysis of 3-5 small clinical trials shows that taking capsicum does not reduce body weight, body fat, or body mass index (BMI) in individuals with a BMI of at least 25 kg/m2 when compared with placebo or no treatment. Freshly chopped chili, fermented red pepper, or capsicum constituents were studied for 4-12 weeks (105194). In one clinical trial included in the analysis, taking capsinoids 3 mg twice daily 30 minutes prior to eating for 12 weeks reduced abdominal fat by about 1%, but did not significantly reduce body weight, when compared with placebo (40599). In overweight individuals, one small clinical trial shows that taking a specific chili extract 200 mg, formulated with fenugreek dietary fiber for sustained release (Capsifen, Akay Natural Ingredients), providing capsaicinoids 4 mg daily for 28 days reduces body weight and BMI by about 2% when compared with placebo. There was no effect on blood pressure (105196). Capsicum has also been evaluated in combination with other ingredients, with some evidence of benefit. One study evaluated a combination product (Prograde Metabolism) containing capsicum extract (Capsimax, OmniActive Health Technologies), raspberry ketone (Razberi K, Integrity Nutraceuticals), caffeine, garlic root extract, ginger root extract, bitter orange fruit (Advantra Z, Nutratech Inc), L-theanine, and black pepper fruit extract (Biperine, Sabinsa Corporation) twice daily for 8 weeks (40802).
• Overall mortality. Eating chili may be beneficial for preventing mortality. It is unclear if taking capsicum supplements is beneficial for preventing overall mortality. Details: Population research has found that consuming chili is associated with a reduced risk of overall mortality. In one study, eating chili more than four times weekly was associated with a 23% reduced odds of overall mortality when compared with never or rarely consuming chili (105208). Other population research has found that any consumption of hot red chili peppers is associated with a 13% reduced odds of mortality when compared with not eating these peppers (105210). Also, eating spicy foods at least once each week, consisting mainly of fresh chili pepper, dried chili pepper, chili sauce, or chili oil, was associated with at least a 10% reduced risk of death when compared with eating these foods less than once a week (105211).
• Peptic ulcers. It is unclear if oral capsicum is beneficial for peptic ulcers. Details: Population research has found that eating capsicum fruit (chili) an average of 24 times per month is associated with a reduced likelihood of having an ulcer when compared with eating chili an average of 8 times per month. This applies to chili in the form of chili powder, chili sauce, curry powder, and other chili-containing foods (12053). However, clinical research shows that consuming chili peppers 1 gram three times daily for 4 weeks does not improve duodenal ulcer healing when compared to control (40828).
• Peripheral neuropathy. Preliminary clinical research suggests that topical capsaicin might be beneficial for reducing peripheral neuropathy pain. Details: Preliminary clinical research shows that applying patches containing the capsicum constituent capsaicin 8% (Qutenza, NeurogesX Inc.) reduces pain in people with non-diabetic peripheral neuropathy (96452,111516). Up to four patches, applied to different painful areas, are used at one time and are left in place for 30 minutes on the feet, or 60 minutes on other parts of the body such as the legs, torso, hands, arms, head, or neck (96452). After an interval of at least 90 days, treatment can be repeated, with new patches applied for 30-60 minutes (99407). There is an average 27% reduction in pain when compared to baseline, lasting up to 12 weeks (96452). Another similar study reported a decrease of 1 point, on a 10-point pain scale, in the typical daily pain intensity (99407). The validity of these findings is limited by methodological problems, including the lack of control groups. Further research shows that using a single application of up to four capsaicin 8% patches for 30-60 minutes, or taking pregabalin orally, 150-600 mg in 2-3 divided doses daily for 8 weeks, reduces the intensity and area of dynamic mechanical allodynia (DMA, pain evoked by light brushing of the skin) in people with non-diabetic peripheral neuropathy. Complete resolution of DMA occurred in 24% of people using the patches, and 12% of those taking pregabalin (99408). The validity of these findings is limited by methodological problems, including a lack of blinding.
• Prurigo nodularis. It is unclear if topical capsaicin is beneficial for prurigo nodularis. Details: Preliminary clinical research shows that applying a cream containing the active capsicum constituent, capsaicin 0.025% to 0.3%, 4-6 times daily improves burning sensations, erythema, pruritus, and healing of skin lesions over a period of 2 weeks to 33 months when compared to baseline. Symptoms may return after discontinuation of therapy (10650).
• Sinonasal polyposis. It is unclear if intranasal capsaicin is beneficial for sinonasal polyposis. Details: Preliminary clinical research in patients with severe sinonasal polyposis shows that intranasal application of 0.5 mL of a 30 mmol/L capsaicin solution to each nostril for 3 days, followed by 0.5 mL of a 100 mmol/L capsaicin solution for 2 days, can cause significant subjective improvement in symptoms as well as objective improvement in nose/sinus air volume and endoscopy scores; however, capsaicin does not seem to significantly affect eosinophil cationic protein levels (14359).
• Swallowing dysfunction. Preliminary research shows that oral capsaicin might be beneficial for improving swallowing ability. Details: Preliminary clinical research shows that elderly patients at risk for aspiration pneumonia due to swallowing dysfunction have improved swallowing reflexes after dissolving a lozenge containing capsaicin 1.5 mcg in the mouth before each meal when compared with using a placebo lozenge (13100). Preliminary clinical research also shows that capsaicin may be beneficial in patients with swallowing dysfunction due to stroke (102278,105192). One study shows that taking 1 mL of nectar containing capsaicin 150 mcM/L with each meal daily for 3 weeks, in addition to thermal tactile stimulation, improves eating and swallowing when compared with using thermal tactile stimulation and placebo nectar (102278). Another study shows that 20 minutes of stimulation with an ice swab containing capsaicin 0.15 mM before lunch and dinner daily for three weeks modestly improves the ability to swallow water when compared with ice stimulation alone. After treatment, approximately 70% of those using the capsaicin ice were able to drink the water without choking, compared with only 33% in those using ice alone (105192). Capsaicin solution has also been administered by nebulizer. A clinical study in patients with swallowing dysfunction secondary to hemorrhagic stroke shows that inhaling capsaicin solution twice daily for one week reduces the incidence of post-swallow residue and pulmonary infection and increases number of coughs in response to capsaicin compared with placebo. However, treatment with nebulized capsaicin does not reduce the number of patients with swallow or cough reflexes compared with control (111518). More evidence is needed to rate capsicum for these uses.

(Read more about CAPSICUM)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• ACE inhibitor-induced cough. It is unclear if oral marshmallow root is beneficial in patients with cough due to ACE inhibitors. Details: A small clinical study in patients with ACE inhibitor-induced cough shows that taking marshmallow root 40 mg (20 drops) three times daily for 4 weeks improves cough when compared to baseline (62027). The validity of this finding is limited by the lack of a control group.
• Atopic dermatitis (eczema). It is unclear if topical marshmallow is beneficial in children with eczema. Details: A very small clinical study in children ages 3 months to 12 years with a recent diagnosis of mild to moderate eczema shows that applying a marshmallow 1% ointment twice daily for 1 week and then three times weekly for 3 weeks seems to reduce symptoms, as measured on the SCORing Atopic Dermatitis (SCORAD) scale, when compared with applying hydrocortisone 1% ointment (105437). This finding is limited by the large number of drop-outs due to non-compliance, most of which were in the marshmallow group.
• Breast engorgement. It is unclear if topical marshmallow is beneficial in women with this condition. Details: A small clinical study in breastfeeding women with breast engorgement shows that applying a compress containing 40-50 mL of a solution made from marshmallow leaves and stems 3 times daily for 2 days in conjunction with standard treatment improves patient-reported breast engorgement scores when compared with standard treatment alone. Standard treatment consisted of massage and alternating warm and cold compresses before and after breastfeeding (92845).
• Constipation. Although there is interest in using oral marshmallow for constipation, there is insufficient reliable information about the clinical effects of marshmallow for this condition.
• Cough. Although there is interest in using oral marshmallow for cough, there is insufficient reliable information about the clinical effects of marshmallow for this condition.
• Diarrhea. Although there is interest in using oral marshmallow for diarrhea, there is insufficient reliable information about the clinical effects of marshmallow for this condition.
• Fever. It is unclear if topical marshmallow is beneficial for pediatric fever. Details: A moderate-sized clinical study in children aged 6 months-10 years with fever receiving rectal acetaminophen shows that applying marshmallow extract body wash and lukewarm water reduces the time to defervescence by 8 minutes when compared with lukewarm water alone, but does not improve the change in body temperature, number of acetaminophen doses given, or incidence of fever recurrence (112375). However, the interpretation of these findings is limited to patients without fevers greater than 40 degrees Celsius or history of febrile seizures since these patients were not studied.
• Leishmania lesions. Topical marshmallow has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research suggests that the topical application of an herbal extract containing a combination of marshmallow and Althaea rosa to affected areas for 5 days can help promote curing of Leishmania lesions (62020).
• Respiratory tract infections. Although there is interest in using oral marshmallow for respiratory tract infections, there is insufficient reliable information about the clinical effects of marshmallow for this condition.
• Vaginal candidiasis. It is unclear if vaginal marshmallow is beneficial for vulvovaginal candidiasis. Details: A small clinical study in adults with vulvovaginal candidiasis shows that applying a vaginal cream comprised of marshmallow extract 4% and clotrimazole 1% daily for 7 days improves itching, dyspareunia, and dysuria at 7 days when compared with clotrimazole 1% alone. At 30 days, the marshmallow intervention also results in fewer positive yeast cultures and sustained reduction in itching (112371). However, the validity of these results is limited by significant differences between groups at baseline for dyspareunia and dysuria, and lack of adjustment for multiple comparisons which can increase false positive findings. Additionally, all primary outcomes were patient-reported.
• Venous leg ulcers. Although there is interest in using topical marshmallow for venous leg ulcers, there is insufficient reliable information about the clinical effects of marshmallow for this condition.
• Wounds. Although there is interest in using topical marshmallow for wounds, there is insufficient reliable information about the clinical effects of marshmallow for this condition. More evidence is needed to rate marshmallow for these uses.

(Read more about MARSHMALLOW)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Asthma. Although there is interest in using oral mullein for asthma, there is insufficient reliable information about the clinical effects of mullein for this condition.
• Bronchitis. Although there is interest in using oral mullein for bronchitis, there is insufficient reliable information about the clinical effects of mullein for this condition.
• Cough. Although there is interest in using oral mullein for cough, there is insufficient reliable information about the clinical effects of mullein for this purpose.
• Diarrhea. Although there is interest in using oral mullein for diarrhea, there is insufficient reliable information about the clinical effects of mullein for this purpose.
• Hemorrhoids. Although there is interest in using topical mullein for hemorrhoids, there is insufficient reliable information about the clinical effects of mullein for this purpose.
• Influenza. Although there is interest in using oral mullein for influenza, there is insufficient reliable information about the clinical effects of mullein for this condition.
• Migraine headache. Although there is interest in using oral mullein for migraine headache, there is insufficient reliable information about the clinical effects of mullein for this condition.
• Otitis media. Topical mullein has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that applying a specific combination product containing mullein, garlic, calendula, and St. John's wort in olive oil (Otikon Otic Solution, Healthy-On Ltd), five drops into the affected ear three times daily for 3 days, reduces ear pain in children and adolescents with otitis media (39500,39552). Whether this effect is due to mullein, one of the other ingredients, or the combination is unclear.
• Pneumonia. Although there is interest in using oral mullein for pneumonia, there is insufficient reliable information about the clinical effects of mullein for this condition.
• Wound healing. It is unclear if topical mullein is helpful for healing episiotomy wounds. Details: In preliminary clinical research in primiparous patients with episiotomy wounds, applying a cream containing mullein flower extract 7.5%, 2 cm twice daily for 10 days, improves redness, edema, ecchymoses, discharge, and wound edge adhesions (REEDA score for episiotomy wound healing) at 10 days, but not earlier, when compared with placebo (107873). More evidence is needed to rate mullein for these uses.

(Read more about MULLEIN)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Aging skin. It is unclear if topical rutin is beneficial for aging skin. Details: Preliminary clinical research shows that topical application of a cream containing rutin 2% twice daily for 4 weeks reduces signs of skin aging around the eye in females aged 30-50 years. Skin dermal density is improved by 20%, area of crow's feet is reduced by 26%, and the number of wrinkles under the eye is reduced by 53% when compared with placebo (92236).
• Autism spectrum disorder. Oral rutin has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in children 4-10 years-old with autism spectrum disorder shows that taking a product containing rutin 3 mg/kg, luteolin 10 mg/kg, and quercetin 7 mg/kg daily for 26 weeks improves aspects of behavior, such as hyperactivity, irritability, and lethargy, by a moderate to large amount when compared to baseline. It also seems to improve some indices of functioning, such as daily living and social behavior, by a small amount. These improvements were considered to be greater than expected when taking aging into consideration; however, no placebo was used in this study (96765).
• Diabetes. It is unclear if oral rutin is beneficial for diabetes. Details: A small clinical study in adults with type 2 diabetes conducted in Iran shows that taking rutin 500 mg twice daily for 3 months reduces fasting blood glucose and glycated hemoglobin by approximately 40 mg/dL and 1%, respectively, and modestly reduces triglycerides and total and low-density lipoprotein cholesterol when compared with placebo (112182). The interpretation of these findings is limited by the omission of data regarding concurrent diabetes medications. A small observational study in patients with a family history of type 1 diabetes shows that taking a specific product (Mucos Pharma) containing rutin 100 mg, trypsin 48 mg, and bromelain 90 mg daily for 24 months is not associated with reduced incidence of type 1 diabetes at 8 years (99472).
• Exercise-induced respiratory infections. Oral rutin has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in non-elite male runners shows that taking a combination product (Wobenzym Plus, Mucos Pharma) providing rutin 600-1200 mg, trypsin 288-576 mg, and bromelain 540-1080 mg daily for 3 weeks, starting one week before a marathon, does not reduce the risk of a post-race respiratory tract infection when compared with placebo (96766).
• Hemorrhoids. Although there is interest in using oral rutin for hemorrhoids, there is insufficient reliable information about the clinical effects of rutin for this condition.
• Inflammatory bowel disease (IBD). Although there is interest in using oral rutin for IBD, there is insufficient reliable information about the clinical effects of rutin for these conditions.
• Lymphedema. Oral rutin has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Some clinical research in patients who have undergone a mastectomy shows that taking a specific combination product containing rutin, pancreatin, papain, bromelain, trypsin, and chymotrypsin (Wobenzym N, Mucos Pharma) daily for 7 weeks reduces arm swelling associated with lymphedema when compared with diuretics (24560). Also, preliminary clinical research in patients with primary or secondary lymphedema of the upper or lower limbs shows that taking a combination product containing rutin 300 mg, bromelain 100 mg, and sweet clover 100 mg daily for 6 months decreases pitting, limb volume, pain, and quality of life when compared to baseline (103298). The validity of these findings is limited by the lack of a comparator group. Also, it is unclear if these effects are due to rutin, other ingredients, or the combination.
• Multiple sclerosis (MS). Oral rutin has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A preliminary clinical study in patients with relapsing-remitting MS shows that taking an enzyme combination containing rutin 100 mg, trypsin 48 mg, and bromelain 90 mg per tablet for at least 3 months does not affect the progression of disability, relapse rate, or central nervous system lesions when compared with placebo (99468). The validity of these results are limited by the short duration of treatment.
• Obesity. It is unclear if oral rutin is beneficial for obesity. Details: In Japanese adults with a body mass index (BMI) of 23-30 kg/m2, a small clinical trial shows that taking a specific monoglucosyl rutin ( αG Rutin PS) 200 mg or 400 mg daily for 8 weeks reduces the area of visceral fat by 2.4 cm and 3.5 cm, respectively, compared with an increase of 5.2 cm in those taking placebo. However, there were no differences between groups in the actual value of visceral fat, changes in total fat or subcutaneous fat, BMI, body weight, abdominal circumference, or cholesterol or triglyceride levels (105298).
• Oral mucositis. Although there is interest in using oral rutin for oral mucositis, there is insufficient reliable information about the clinical effects of rutin for this condition.
• Osteoarthritis. Oral rutin has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research shows that taking a specific combination product (Wobenzym PS, formerly Phlogenzym, Mucos Pharma) at a dose providing up to 600 mg rutin, 288 mg trypsin, and 540 mg bromelain daily for 3-12 weeks, is as effective as diclofenac for relieving pain and improving knee function in patients with painful osteoarthritis of the knee. This product also reduces the need for rescue medication by 95% when compared with placebo (6252,91104,99467,99477).
• Postoperative swelling. Oral rutin has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small preliminary clinical study in patients undergoing surgery of the jaw shows that taking an enzyme combination of rutin 200 mg, trypsin 96 mg, and bromelain 180 mg twice daily for 5 days in addition to standard treatment reduces soft-tissue thickness (indicating the amount of swelling) at most of the nine assessed facial points when compared to control (99476).
• Sprains. Oral rutin has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A clinical study in patients with a sprained ankle shows that taking a specific enzyme combination (Phlogenzym, Mucos Pharma) containing rutin 100 mg, trypsin 48 mg, and bromelain 90 mg, or taking different combinations of the individual enzymes three times daily for 10 days, is no more effective for relieving pain than placebo (99473).
• Stroke. Although there is interest in using oral rutin for stroke prevention, there is insufficient reliable information about the clinical effects of rutin for this purpose.
• Sunburn. Although there is interest in using topical rutin for sunburn prevention, there is insufficient reliable information about the clinical effects of rutin for this purpose.
• Varicose veins. Although there is interest in using oral rutin for varicose veins, there is insufficient reliable information about the clinical effects of rutin for this condition. More evidence is needed to rate rutin for these uses.

(Read more about RUTIN)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Bruises. Although there has been interest in using topical sweet clover for bruises, there is insufficient reliable information about the clinical effects of sweet clover for this purpose.
• Chronic venous insufficiency (CVI). Oral sweet clover has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Limited clinical evidence shows that taking a combination of sweet clover extract 600 mg and rutin 150 mg daily might improve problems associated with CVI, such as varicose veins (1). It is unclear if this effect is due to sweet clover, rutin, or the combination.
• Diabetic foot ulcers. Although there has been interest in using oral, topical, and intravenous sweet clover for diabetic foot ulcers, there is insufficient reliable information about the clinical effects of sweet clover for this purpose.
• Diabetic neuropathy. It is unclear if oral sweet clover is beneficial in patients with diabetic neuropathy. Details: A small clinical study in patients with type 2 diabetes and diabetic neuropathy shows that taking a specific sweet clover extract (Angipars, Rose Pharmed Co.) 100 mg twice daily for 12 weeks does not improve symptoms of diabetic neuropathy (95172).
• Hemorrhoids. Although there has been interest in using oral sweet clover for hemorrhoids, there is insufficient reliable information about the clinical effects of sweet clover for this purpose. More evidence is needed to rate sweet clover for these uses.

(Read more about SWEET CLOVER)

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, parenterally, or rectally and appropriately. Caffeine has Generally Recognized As Safe (GRAS) status in the US (4912,98806). Caffeine is also an FDA-approved product and a component of several over-the-counter and prescription products (4912,11832). According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, doses of caffeine up to 400 mg daily are not associated with significant adverse cardiovascular, bone, behavioral, or reproductive effects in healthy adults (11733,98806). The US Dietary Guidelines Advisory Committee states that there is strong and consistent evidence that consumption of caffeine 400 mg daily is not associated with increased risk of major chronic diseases, such as cardiovascular disease or cancer, in healthy adults (98806). This amount of caffeine is similar to the amount of caffeine found in approximately 4 cups of coffee. Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine from caffeine-containing natural ingredients such as coffee or green tea does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product.

POSSIBLY UNSAFE ...when used orally, long-term or in high doses (91063). Chronic use, especially in large amounts, can produce tolerance, habituation, psychological dependence, and other adverse effects (3719). Acute use of high doses, typically above 400 mg daily, has been associated with significant adverse effects such as tachyarrhythmia and sleep disturbances (11832). Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine from caffeine-containing natural ingredients such as coffee or green tea does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product.

LIKELY UNSAFE ...when used orally in very high doses. The fatal acute oral dose of caffeine is estimated to be 10-14 grams (150-200 mg/kg). Serious toxicity can occur at lower doses depending on variables in caffeine sensitivity such as smoking, age, or prior caffeine use (11832,95700,97454,104573). Caffeine products sold to consumers in highly concentrated or pure formulations are considered to a serious health concern because these products have a risk of being used in very high doses. Concentrated liquid caffeine can contain about 2 grams of caffeine in a half cup. Powdered pure caffeine can contain about 3.2 grams of caffeine in one teaspoon. Powdered pure caffeine can be fatal in adults when used in doses of 2 tablespoons or less. As of 2018, these products are considered by the FDA to be unlawful when sold to consumers in bulk quantities (95700).

CHILDREN: POSSIBLY SAFE
when used orally or intravenously and appropriately in neonates under the guidance of a healthcare professional (6371,38340,38344,91084,91087,97452). ...when used orally in amounts commonly found in foods and beverages in children and adolescents (4912,11833,36555). Daily intake of caffeine in doses of less than 2.5 mg/kg daily are not associated with significant adverse effects in children and adolescents (11733,98806). Keep in mind that only the amount of ADDED caffeine must be stated on product labels. The amount of caffeine from caffeine-containing natural ingredients such as coffee or green tea does not need to be provided. This can make it difficult to determine the total amount of caffeine in a given product.

PREGNANCY: POSSIBLY SAFE
when used orally in amounts commonly found in foods. Intakes of caffeine should be monitored during pregnancy. Caffeine crosses the human placenta, but is not considered a teratogen (38048,38252,91032). Fetal blood and tissue levels are similar to maternal concentrations (4260). The use of caffeine during pregnancy is controversial; however, moderate consumption has not been associated with clinically important adverse fetal effects (2708,2709,2710,2711,9606,16014,16015,98806,108814). In some studies consuming amounts over 200 mg daily is associated with a significantly increased risk of miscarriage (16014,37960). This increased risk seems to occur in those with genotypes that confer a slow rate of caffeine metabolism (98806). According to a review by Health Canada, and a subsequent large meta-analysis conducted in the US, up to 300 mg daily can be consumed during pregnancy without an increased risk of spontaneous abortion, stillbirth, preterm birth, fetal growth retardation, or congenital malformations (11733,98806). However, observational research in a Norwegian cohort found that caffeine consumption is associated with a 16% increased odds of the baby being born small for gestational age when compared with no consumption (100369,103707). The same Norwegian cohort found that low to moderate caffeine consumption during pregnancy is not associated with changes in neurodevelopment in children up to 8 years of age (103699). Advise patients to keep caffeine consumption below 300 mg daily during pregnancy. This is similar to the amount of caffeine in about 3 cups of coffee or tea.

PREGNANCY: POSSIBLY UNSAFE
when used orally in amounts over 300 mg daily. Caffeine crosses the placenta, producing fetal blood concentrations similar to maternal levels (4260,98806). Consumption of caffeine in amounts over 300 mg daily is associated with a significantly increased risk of miscarriage in some studies (16014,98806). Advise patients to keep caffeine consumption below 300 mg daily during pregnancy. This is similar to the amount of caffeine in about 3 cups of coffee or tea. Additionally, high doses of caffeine throughout pregnancy have resulted in symptoms of caffeine withdrawal in newborn infants (9891). High doses of caffeine have also been associated with spontaneous abortion, premature delivery, and low birth weight (2709,2711,91033,91048,95949). In a cohort of mother/infant pairs with a median maternal plasma caffeine level of 168.5 ng/mL (range 29.5-650.5 ng/mL) during pregnancy, birth weights and lengths were lower in the 4th quartile of caffeine intake compared with the 1st. By age 7, heights and weights were lower by 1.5 cm and 1.1 kg respectively. In another cohort of mother/infant pairs with higher maternal pregnancy plasma caffeine levels, median 625.5 ng/mL (range 86.2 to 1994.7 ng/mL), heights at age 8 were 2.2 cm lower, but there was no difference in weights (109846).

LACTATION: POSSIBLY SAFE
when used orally in amounts commonly found in foods. Caffeine intake should be closely monitored while breast-feeding. During lactation, breast milk concentrations of caffeine are thought to be approximately 50% of serum concentrations and caffeine peaks in breastmilk approximately 1-2 hours after consumption (23590).

LACTATION: POSSIBLY UNSAFE
when used orally in large amounts. Caffeine is excreted slowly in infants and may accumulate. Caffeine can cause sleep disturbances, irritability, and increased bowel activity in breast-fed infants exposed to caffeine (2708,6026).

(Read more about CAFFEINE)

LIKELY SAFE ...when used orally in amounts typically found in food. Capsicum has Generally Recognized as Safe (GRAS) status in the US (4912). ...when used topically and appropriately (7038,10650,105345). The active capsicum constituent capsaicin is an FDA-approved ingredient used in certain over-the-counter, topical preparations (272).

POSSIBLY SAFE ...when used orally and appropriately, short-term in medicinal amounts. A specific sustained-release chili extract (Capsifen) has been used safely in doses of up to 200 mg daily, for up to 28 days (105196). ...when used intranasally and appropriately, short-term. Capsicum-containing nasal sprays, suspensions, and swabs seem to be safe when applied multiple times over 24 hours or when applied daily or every other day for up to 14 days. Although no serious side effects have been reported in clinical trials, intranasal application of capsicum-containing products can be very painful (14322,14324,14328,14329,14351,14352,14353,14356,14357) (14358,14359,14360,15016,105204). POSSIBLY UNSAFE when used orally, long-term or in high doses. There is concern that long-term use or use of excessive doses might be linked to hepatic or kidney damage, as well as hypertensive crisis (12404,40569,40606). There is insufficient reliable information available about the safety of capsicum when injected.

CHILDREN: POSSIBLY UNSAFE
when used topically in children under 2 years old (272). There is insufficient reliable information available about the safety of capsicum when used orally in children.

PREGNANCY: LIKELY SAFE
when used topically and appropriately (272).

PREGNANCY: POSSIBLY SAFE
when used orally and appropriately, short-term. Capsicum 5 mg daily has been used for up to 28 days during the latter half of the second trimester and the third trimester (96457).

LACTATION: LIKELY SAFE
when used topically and appropriately (272).

LACTATION: POSSIBLY UNSAFE
when used orally. Dermatitis can sometimes occur in infants when foods heavily spiced with capsicum peppers are ingested during lactation (739). Also, observational research suggests that intake of raw capsicum peppers during pregnancy is associated with an increased risk of sensitization to inhalant allergens in children by the age of 2 years (41021).

(Read more about CAPSICUM)

LIKELY SAFE ...when marshmallow root and leaf are used in amounts commonly found in foods. Marshmallow root has Generally Recognized As Safe (GRAS) status for use in foods in the US (4912).

POSSIBLY SAFE ...when marshmallow root and leaf are used orally in medicinal amounts (4,12). ...when used topically (4,62020). There is insufficient reliable information available about the safety of marshmallow flower.

PREGNANCY AND LACTATION:
Insufficient reliable information available.

(Read more about MARSHMALLOW)

LIKELY SAFE ...when used orally in amounts found in foods, such as fruits and vegetables.

POSSIBLY SAFE ...when used orally in medicinal amounts, short-term. Rutin has been used with apparent safety at doses of up to 600 mg daily for up to 12 weeks (6252,24560,91104,96766,105298). ...when applied topically as a cream (92236,99258,99260).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally in amounts commonly found in foods. There is insufficient reliable information available about the use of supplemental rutin; avoid amounts greater than those found in foods.

(Read more about RUTIN)

POSSIBLY SAFE ...when preparations of the flowering branch and leaf are used orally in moderate amounts based on clinical use (1,2,18). ...when sweet clover extract is used at a dose of 100 mg for up to 12 weeks (95172).

POSSIBLY UNSAFE ...when excessive amounts of some preparations are used orally because of the potential for transient liver injury. Some researchers suggest that sweet clover intake should contain no more than coumarin 5 mg daily (18,95166).

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

(Read more about SWEET CLOVER)

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).

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ADENOSINE (Adenocard) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, caffeine might decrease the vasodilatory effects of adenosine and interfere with its use prior to stress testing.  Details Some evidence shows that caffeine is a competitive inhibitor of adenosine and can reduce the vasodilatory effects of adenosine in humans (38172). However, other research shows that caffeine does not seem to affect supplemental adenosine because high interstitial levels of adenosine overcome the antagonistic effects of caffeine (11771). It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests (11770). However, methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing (11771).

ALCOHOL (Ethanol) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use might increase levels and adverse effects of caffeine.  Details Alcohol reduces caffeine metabolism. Concomitant use of alcohol can increase caffeine serum concentrations and the risk of caffeine adverse effects (6370).

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, caffeine may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.  Details Caffeine is reported to have antiplatelet activity. Theoretically, it might increase the risk of bleeding when used concomitantly with these agents (8028,8029); however, this interaction has not been reported in humans.

ANTIDIABETES DRUGS Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = B Theoretically, taking caffeine with antidiabetes drugs might interfere with blood glucose control.  Details Data are conflicting. Reports claim that caffeine might increase or decrease blood sugar (6024,8646).

CARBAMAZEPINE (Tegretol) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, caffeine might reduce the effects of carbamazepine and increase the risk for convulsions.  Details Animal research suggests that taking caffeine can lower the anticonvulsant effects of carbamazepine and can induce seizures when taken in doses above 400 mg/kg (23559,23561). Human research has shown that taking caffeine 300 mg in three divided doses along with carbamazepine 200 mg reduces the bioavailability of carbamazepine by 32% and prolongs the plasma half-life of carbamazepine 2-fold in healthy individuals (23562).

CIMETIDINE (Tagamet) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Likely •  Level of Evidence = B Theoretically, cimetidine might increase the levels and adverse effects of caffeine.  Details Cimetidine decreases the rate of caffeine clearance by 31% to 42% (11736).

CLOZAPINE (Clozaril) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Caffeine might increase the levels and adverse effects of clozapine and acutely exacerbate psychotic symptoms.  Details Caffeine might increase the effects and toxicity of clozapine. Caffeine doses of 400-1000 mg per day inhibit clozapine metabolism (5051). Clozapine is metabolized by cytochrome P450 1A2 (CYP1A2). Although researchers speculate that caffeine might inhibit CYP1A2, there is no reliable evidence that caffeine affects CYP1A2. There is also speculation that genetic factors might make some patients more sensitive to an interaction between clozapine and caffeine (13741). In one case report, severe, life-threatening clozapine toxicity and multiorgan system failure occurred in a patient with schizophrenia stabilized on clozapine who consumed caffeine 600 mg daily (108817).

CONTRACEPTIVE DRUGS Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Theoretically, contraceptive drugs might increase the levels and adverse effects of caffeine.  Details Oral contraceptives decrease the rate of caffeine clearance by 40-65% (2714,11737).

CYTOCHROME P450 1A2 (CYP1A2) INHIBITORS Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use might increase the levels and adverse effects of caffeine.  Details Caffeine is metabolized by CYP1A2. Theoretically, drugs that inhibit CYP1A2 may decrease the rate of caffeine clearance and increase caffeine levels (5051,11741).

DIPYRIDAMOLE (Persantine) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Theoretically, caffeine might decrease the vasodilatory effects of dipyridamole and interfere with its use prior to stress testing.  Details Caffeine inhibits dipyridamole-induced vasodilation (11770,11772). It is recommended that methylxanthines and methylxanthine-containing products be stopped 24 hours prior to pharmacological stress tests (11770). Methylxanthines appear more likely to interfere with dipyridamole (Persantine) than adenosine-induced stress testing (11771).

DISULFIRAM (Antabuse) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Theoretically, disulfiram use might increase the levels and adverse effects of caffeine.  Details Disulfiram decreases the rate of caffeine clearance (11840).

DIURETIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, using caffeine with diuretic drugs might increase the risk of hypokalemia.  Details Caffeine, especially in excessive amounts, can reduce potassium levels due to stimulation of the sodium-potassium pump (23579,37905,37953,38003,38034). Diuretics can also cause lower potassium levels.

EPHEDRINE Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = D Theoretically, concomitant use might increase the risk for stimulant adverse effects.  Details Use of ephedrine with caffeine can increase the risk of stimulatory adverse effects. There is evidence that using ephedrine with caffeine might increase the risk of serious life-threatening or debilitating adverse effects such as hypertension, myocardial infarction, stroke, seizures, and death (1275,6486,10307).

ESTROGENS Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Theoretically, estrogens might increase the levels and adverse effects of caffeine.  Details Estrogen inhibits caffeine metabolism (2714,23570).

ETHOSUXIMIDE (Zarontin) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, caffeine might reduce the effects of ethosuximide and increase the risk for convulsions.  Details Animal research suggests that caffeine 92.4 mg/kg can decrease the anticonvulsant activity of ethosuximide (23560). However, this effect has not been reported in humans.

FELBAMATE (Felbatol) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, caffeine might reduce the effects of felbamate and increase the risk for convulsions.  Details Animal research suggests that a high dose of caffeine 161.7 mg/kg can decreases the anticonvulsant activity of felbamate (23563). However, this effect has not been reported in humans.

FLUCONAZOLE (Diflucan) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Theoretically, fluconazole might increase the levels and adverse effects of caffeine.  Details Fluconazole decreases caffeine clearance by approximately 25% (11022).

FLUTAMIDE (Eulexin) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, caffeine might increase the levels and adverse effects of flutamide.  Details In vitro evidence suggests that caffeine can inhibit the metabolism of flutamide (23553). However, this effect has not been reported in humans.

FLUVOXAMINE (Luvox) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = D Theoretically, fluvoxamine might increase the levels and adverse effects of caffeine.  Details Fluvoxamine reduces caffeine metabolism (6370).

LITHIUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, abrupt caffeine withdrawal might increase the levels and adverse effects of lithium.  Details Caffeine has diuretic activity. When abruptly discontinued, it might alter the clearance of lithium (609). There are two case reports of lithium tremor that worsened upon abrupt coffee withdrawal (610).

METFORMIN (Glucophage) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, metformin might increase the levels and adverse effects of caffeine.  Details Animal research suggests that metformin can reduce caffeine metabolism (23571). However, this effect has not been reported in humans.

METHOXSALEN (Oxsoralen) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Theoretically, methoxsalen might increase the levels and adverse effects of caffeine.  Details Methoxsalen reduces caffeine metabolism (23572).

MEXILETINE (Mexitil) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Theoretically, mexiletine might increase the levels and adverse effects of caffeine.  Details Mexiletine reduces caffeine metabolism (1260,11741).

MONOAMINE OXIDASE INHIBITORS (MAOIs) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use might increase the risk of a hypertensive crisis.  Details Caffeine has been shown to inhibit monoamine oxidase (MAO) A and B in laboratory studies (37724,37877,37912,38108). Concomitant intake of large amounts of caffeine with MAOIs might precipitate a hypertensive crisis (15). In a case report, a patient that consumed 10-12 cups of caffeinated coffee and took the MAOI tranylcypromine presented with severe hypertension (91086). Hypertension was resolved after the patient switched to drinking decaffeinated coffee.

NICOTINE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Theoretically, concomitant use might increase the risk of hypertension.  Details Concomitant use of caffeine and nicotine has been shown to have additive cardiovascular effects, including increased heart rate and blood pressure. Blood pressure was increased by 10.8/12.4 mmHg when the agents were used concomitantly (36549).

PENTOBARBITAL (Nembutal) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, caffeine might decrease the effects of pentobarbital.  Details Caffeine might negate the hypnotic effects of pentobarbital (13742).

PHENOBARBITAL (Luminal) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, caffeine might reduce the effects of phenobarbital and increase the risk for convulsions.  Details Animal research suggests that caffeine can decrease the anticonvulsant activity of phenobarbital (23558,23559,23561). However, the exact mechanism of this interaction is unclear.

PHENOTHIAZINES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, phenothiazines might increase the levels and adverse effects of caffeine.  Details Phenothiazines, including perazine, chlorpromazine, levomepromazine, and thioridazine, can reduce the metabolism of caffeine by inhibiting cytochrome P450 1A2 (CYP1A2) (23573,23574).

PHENYLPROPANOLAMINE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Theoretically, phenylpropanolamine might increase the risk of hypertension, as well as the levels and adverse effects of caffeine.  Details Concomitant use of phenylpropanolamine and caffeine might cause an additive increase in blood pressure (11738). Phenylpropanolamine also seems to increase caffeine serum levels (13743).

PHENYTOIN (Dilantin) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, caffeine might reduce the effects of phenytoin and increase the risk for convulsions.  Details Animal research suggests that caffeine can decrease the anticonvulsant activity of phenytoin (23559,23561). The effect does not seem to be related to the seizure threshold-lowering effects of caffeine. However, the exact mechanism of this interaction is unclear.

PIOGLITAZONE (Actos) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, caffeine might increase the levels and clinical effects of pioglitazone.  Details Animal research suggests that caffeine can modestly increase the maximum concentration, area under the curve, and half-life of pioglitazone, and also reduce its clearance. This increased the antidiabetic effects of pioglitazone (108812). However, the exact mechanism of this interaction is unclear.

QUINOLONE ANTIBIOTICS Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Theoretically, quinolone antibiotics might increase the levels and adverse effects of caffeine.  Details Quinolones (also called fluoroquinolones) can decrease caffeine clearance by inhibiting cytochrome P450 1A2 (CYP1A2) enzyme (606,607,608,23554,23555,23556).

RILUZOLE (Rilutek) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use might increase the levels and adverse effects of both caffeine and riluzole.  Details Caffeine and riluzole are both metabolized by cytochrome P450 1A2 (CYP1A2), and concomitant use might reduce the metabolism of one or both agents (11739).

STIMULANT DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = C Theoretically, concomitant use might increase stimulant adverse effects.  Details Due to the central nervous system (CNS) stimulant effects of caffeine, concomitant use with stimulant drugs can increase the risk of adverse effects (11832).

TERBINAFINE (Lamisil) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Theoretically, terbinafine might increase the levels and adverse effects of caffeine.  Details Terbinafine decreases the clearance of intravenous caffeine by 19% (11740).

THEOPHYLLINE Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = C Theoretically, caffeine might increase the levels and adverse effects of theophylline.  Details Large amounts of caffeine might inhibit theophylline metabolism (11741).

TIAGABINE (Gabitril) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, caffeine might increase the levels and adverse effects of tiagabine.  Details Animal research suggests that chronic caffeine administration can increase the serum concentrations of tiagabine. However, concomitant use does not seem to reduce the antiepileptic effects of tiagabine (23561).

TICLOPIDINE (Ticlid) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, ticlopidine might increase the levels and adverse effects of caffeine.  Details In vitro evidence suggests that ticlopidine can inhibit caffeine metabolism (23557). However, this effect has not been reported in humans.

VALPROATE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, caffeine might reduce the effects of valproate and increase the risk for convulsions.  Details Animal research suggests that caffeine can decrease the anticonvulsant activity of valproate (23558,23559,23561,37882). However, the exact mechanism of this interaction is unclear.

VERAPAMIL (Calan, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, verapamil might increase the levels and adverse effects of caffeine.  Details Verapamil increases plasma caffeine concentrations by 25% (11741).

(Read more about CAFFEINE)

ACE INHIBITORS (ACEIs) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, using topical capsaicin may increase the risk of ACE inhibitor-induced cough.  Details There is one case report of a topically applied capsaicin cream contributing to the cough reflex in a patient using an ACEI (12414). However, it is unclear if this interaction is clinically significant.

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Theoretically, capsicum may increase the risk of bleeding if used with anticoagulant or antiplatelet drugs.  Details In vitro research shows that capsicum might increase the effects of antiplatelet drugs (12406,12407). Also, population research shows that capsicum is associated with an increased risk of self-reported bleeding in patients taking warfarin (12405,20348). However, clinical research shows that taking a single dose of capsaicin (Asian Herbex Ltd.), the active ingredient in capsicum, 400-800 mcg orally in combination with aspirin 500 mg does not decrease platelet aggregation when compared with taking aspirin 500 mg alone. Also, there was no notable effect on measures of platelet aggregation with capsaicin (92990). It is unclear whether capsaicin must be used in more than a single dose to affect platelet aggregation.

ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, taking capsicum with antidiabetes drugs might increase the risk of hypoglycemia.  Details Preliminary clinical research shows that consuming capsicum 5 grams along with a glucose drink attenuates the rise in plasma glucose after 30 minutes by 21%, decreases the 2-hour postprandial area under the curve of plasma glucose by 11%, and increases the 2-hour postprandial area under the curve of plasma insulin by 58% in healthy individuals when compared with placebo (40453,40614). Other clinical research shows that taking capsicum 5 mg daily for 28 days significantly reduces postprandial blood glucose and insulin levels, but not fasting blood glucose and insulin levels, in patients with gestational diabetes (96457).

ASPIRIN Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking capsicum with aspirin might reduce the bioavailability of aspirin.  Details Animal research shows that acute or chronic intake of capsicum pepper reduces oral aspirin bioavailability (22617). This has not been shown in humans.

CIPROFLOXACIN (Cipro) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking capsicum with ciprofloxacin might increase levels and adverse effects of ciprofloxacin.  Details Animal research shows that concomitant use of capsaicin, the active constituent of capsicum, and ciprofloxacin increases the bioavailability of ciprofloxacin by up to 70% (22613).

THEOPHYLLINE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking capsicum with theophylline might increase the levels and adverse effects of theophylline.  Details In animal research, oral administration of capsicum reduced excretion of theophylline (12405). However, capsicum does not seem to affect the pharmacokinetics of theophylline when administered intravenously (22616).

(Read more about CAPSICUM)

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, marshmallow flower might have antiplatelet effects.  Details Animal research suggests that marshmallow flower extract has antiplatelet effects (92846). However, the root and leaf of marshmallow, not the flower, are the plant parts most commonly found in dietary supplements. Theoretically, use of marshmallow flower with anticoagulant/antiplatelet drugs can have additive effects, and might increase the risk for bleeding in some patients.

LITHIUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, due to potential diuretic effects, marshmallow might reduce excretion and increase levels of lithium.  Details Marshmallow is thought to have diuretic properties. To avoid lithium toxicity, the dose of lithium might need to be decreased when used with marshmallow.

ORAL DRUGS Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, mucilage in marshmallow might impair absorption of oral drugs.  Details Marshmallow contains mucilage which can affect oral drug absorption (1,11,12,19). To avoid changes in absorption, take marshmallow 30-60 minutes after oral medications.

(Read more about MARSHMALLOW)

(Read more about MULLEIN)

ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking rutin with antidiabetes drugs might increase the risk of hypoglycemia.  Details Animal research suggests that rutin has hypoglycemic effects (105299).

(Read more about RUTIN)

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, fresh sweet clover might increase the risk of bleeding when used with anticoagulant or antiplatelet drugs.  Details Fresh sweet clover contains coumarinic acids (18), which are converted to free coumarins during drying (1,8,18). Dicoumarol, which has anticoagulant activity, also has been found in some sweet clover preparations and can be formed if fresh sweet clover is allowed to spoil (1).

HEPATOTOXIC DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, concomitant use of sweet clover with hepatoxic drugs might increase the risk of hepatotoxicity.  Details Orally, large amounts of sweet clover can cause transient liver injury in susceptible individuals, possibly due to coumarin content (18). In one case report, a patient with multiple sclerosis developed jaundiced palms and a slight elevation in serum alanine aminotransferase (ALT) after taking sweet clover containing coumarin 10 mg daily for 3 years. Two weeks after starting therapy with subcutaneous interferon (IFN)-beta 1b, aspartate transaminase (AST) and ALT levels increased to 7 and 17 times the upper limit of normal, respectively. Levels normalized after discontinuation of both products. Subsequent use of IFN-beta 1a alone, without sweet clover, resulted in only a very slight increase in AST (95166).

(Read more about SWEET CLOVER)

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 ...Caffeine in moderate doses is typically well tolerated.
Most Common Adverse Effects:
Orally: Anxiety, dependence with chronic use, diarrhea, diuresis, gastric irritation, headache, insomnia, muscular tremors, nausea, and restlessness.
Serious Adverse Effects (Rare):
Orally: Stroke has been reported rarely.

Cardiovascular ...Caffeine can temporarily increase blood pressure. Usually, blood pressure increases 30 minutes after ingestion, peaks in 1-2 hours, and remains elevated for over 4 hours (36539,37732,37989,38000,38300).
Although acute administration of caffeine can cause increased blood pressure, regular consumption does not seem to increase either blood pressure or pulse, even in mildly hypertensive patients (1451,1452,2722,38335). However, the form of caffeine may play a role in blood pressure increase after a more sustained caffeine use. In a pooled analysis of clinical trials, coffee intake was not associated with an increase in blood pressure, while ingesting caffeine 410 mg daily for at least 7 days modestly increased blood pressure by an average of 4.16/2.41 mmHg (37657). Another meta-analysis of clinical research shows that taking caffeine increases systolic and diastolic blood pressure by approximately 2 mmHg when compared with control. Preliminary subgroup analyses suggest that caffeine may increase blood pressure more in males or at doses over 400 mg (112738).
When used prior to intensive exercise, caffeine can increase systolic blood pressure by 7-8 mmHg (38308). The blood pressure-raising effects of caffeine are greater during stress (36479,38334) and after caffeine-abstinence of at least 24 hours (38241).
Epidemiological research suggests there is no association of caffeine consumption with incidence of hypertension (38190). Habitual coffee consumption also doesn't seem to be related to hypertension, but habitual consumption of sugared or diet cola is associated with development of hypertension (13739).
Epidemiological research has found that regular caffeine intake of up to 400 mg daily is not associated with increased incidence of atrial fibrillation (38018,38076,91028,91034,97451,97453,103708), atherosclerosis (38033), cardiac ectopy (91127), stroke (37804), ventricular arrhythmia (95948,97453), and cardiovascular disease in general (37805,98806). One clinical trial shows that in adults with diagnosed heart failure, consumption of 500 mg of coffee does not result in an increased risk for arrhythmia during exercise (95950). However, caffeine intake may pose a greater cardiovascular risk to subjects that are not regular users of caffeine. For example, in one population study, caffeinated coffee consumption was associated with an increased risk of ischemic stroke in subjects that don't regularly drink coffee (38102). In a population study in Japanese subjects, caffeine-containing medication use was modestly associated with hemorrhagic stroke in adults that do not consume caffeine regularly (91059).
The most common side effect of caffeine in neonates receiving caffeine for apnea is tachycardia (98807).

Dermatologic ...There are several case reports of urticaria after caffeine ingestion (36546,36448,36475).

Endocrine ...Some evidence shows caffeine is associated with fibrocystic breast disease or breast cancer in females; however, this is controversial since findings are conflicting (8043,108806). Restricting caffeine in females with fibrocystic breast conditions doesn't seem to affect breast nodularity, swelling, or pain (8996). A population analysis of the Women's Health Initiative observational study has found no association between consumption of caffeine-containing beverages and the incidence of invasive breast cancer in models adjusted for demographic, lifestyle, and reproductive factors (108806). Also, a dose-response analysis of 2 low-quality observational studies has found that high consumption of caffeine is not associated with an increased risk of breast cancer (108807).
Clinical research in healthy adults shows that an increase consumption of caffeine results in increased insulin resistance (91023).

Gastrointestinal ...Gastrointestinal upset, nausea, diarrhea, abdominal pain, and fecal incontinence may occur with caffeine intake (36466,37755,37806,37789,37830,38138,38136,38223,95956,95963). Also, caffeine may cause feeding intolerance and gastrointestinal irritation in infants (6023). Perioperative caffeine during cardiopulmonary bypass surgery seems to increase the rate of postoperative nausea and vomiting (97451). Caffeine and coffee consumption have been associated with an increase in the incidence of heartburn (37545,37575,38251,38259,38267) and gastrointestinal esophageal reflux disease (GERD) (38329,37633,37631,37603).

Genitourinary ...Caffeine, a known diuretic, may increase voiding, give a sense of urgency, and irritate the bladder (37874,37961,104580). In men with lower urinary tract symptoms, caffeine intake increased the risk of interstitial cystitis/painful bladder syndrome (38115). Excessive caffeine consumption may worsen premenstrual syndrome. Consumption of up to 10 cups of caffeinated drinks daily was associated with increased severity of premenstrual syndrome (38177). Finally, population research shows that exposure to caffeine was not associated with an increased risk of endometriosis (91035).

Immunologic ...Caffeine can cause anaphylaxis in sensitive individuals, although true IgE-mediated caffeine allergy seems to be relatively rare (11315).

Musculoskeletal ...Caffeine can induce or exacerbate muscular tremors (38136,37673,38161). There has also been a report of severe rhabdomyolysis in a healthy 40-year-old patient who consumed an energy drink containing 400 mg of caffeine (4 mg/kg) and then participated in strenuous weightlifting exercise (108818).
Epidemiological evidence regarding the relationship between caffeine use and the risk for osteoporosis is contradictory. Caffeine can release calcium from storage sites and increase its urinary excretion (2669,10202,11317,111489). Females with a genetic variant of the vitamin D receptor appear to be at an increased risk for the detrimental effect of caffeine on bone mass (2669). However, moderate caffeine intake, less than 300 mg daily, does not seem to significantly increase osteoporosis risk in most postmenopausal adults with normal calcium intake (2669,6025,10202,11317). Premature infants treated with intravenous caffeine for apnea of prematurity, have a lower bone mineral content compared with infants who are not treated with caffeine, especially when treatment extends beyond 14 days (111489).

Neurologic/CNS ...Caffeine can cause headaches, anxiety, jitteriness, restlessness, and nervousness (36466,37694,37755,37806,37865,37830,37889,38223,95952). In adolescents, there is an inverse correlation between the consumption of caffeine and various measurements of cognitive function (104579). Insomnia is a frequent adverse effect in children (10755). Caffeine may result in insomnia and sleep disturbances in adults as well (36445,36483,36512,36531,37598,37795,37819,37862,37864,37890)(37968,37971,38091,38242,91022,92952). Additionally, caffeine may exacerbate sleep disturbances in patients with acquired immunodeficiency syndrome (AIDS) (10204). Combining ephedra with caffeine can increase the risk of adverse effects. Jitteriness, hypertension, seizures, temporary loss of consciousness, and hospitalization requiring life support has been associated with the combined use of ephedra and caffeine (2729). Finally, epidemiological research suggests that consuming more than 190 mg of caffeine daily is associated with an earlier onset of Huntington disease by 3.6 years (91078).

Ocular/Otic ...In individuals with glaucoma, coffee consumption and caffeine intake has been found to increase intraocular pressure (8540,36464,36465,37670). The magnitude of this effect seems to depend on individual tolerance to caffeine. Some research in healthy young adults shows that caffeine increases intraocular pressure to a greater degree in low-consumers of caffeine (i.e., 1 cup of coffee or less daily) when compared to high-consumers (i.e., those consuming 2 cups of coffee or more daily) (100371). The peak increase of intraocular pressure seems to occur at about 1.5 hours after caffeine ingestion, and there is no notable effect 4 hours after ingestion (36462,100371).

Oncologic ...Most human studies which have examined caffeine or methylxanthine intake have found that they do not play a role in the development of various cancers, including breast, ovarian, brain, colon, rectal, or bladder cancer (37641,37737,37775,37900,38050,38169,38220,91054,91076,108806).

Psychiatric ...Caffeine may lead to habituation and physical dependence (36355,36453,36512,36599), with amounts as low as 100 mg daily (36355,36453). An estimated 9% to 30% of caffeine consumers could be considered addicted to caffeine (36355). Higher doses of caffeine have caused nervousness, agitation, anxiety, irritability, delirium, depression, sleep disturbances, impaired attention, manic behavior, psychosis and panic attacks (36505,37717,37818,37839,37857,37982,38004,38017,38028,38072)(38079,38138,38306,38325,38331,38332,97464). Similar symptoms have been reported in a caffeine-naïve individual experiencing fatigue and dehydration after a dose of only 200 mg, with resolution of symptoms occurring within 2 hours (95952).
Withdrawal: The existence or clinical importance of caffeine withdrawal is controversial. Some researchers think that if it exists, it appears to be of little clinical significance (11839). Headache is the most common symptom, due to cerebral vasodilation and increased blood flow (37769,37991,37998). Other researchers suggest symptoms such as tiredness and fatigue, decreased energy, alertness and attentiveness, drowsiness, decreased contentedness, depressed mood, difficulty concentration, irritability, and lack of clear-headedness are typical of caffeine withdrawal (13738). Withdrawal symptoms typically occur 12-24 hours after the last dose of caffeine and peak around 48 hours (37769,36600). Symptoms may persist for 2-9 days. Withdrawal symptoms such as delirium, nausea, vomiting, rhinorrhea, nervousness, restlessness, anxiety, muscle tension, muscle pains, and flushed face have been described. However, these symptoms may be from nonpharmacological factors related to knowledge and expectation of effects. Clinically significant symptoms caused by caffeine withdrawal may be uncommon (2723,11839). In a case report, caffeine consumption of 560 mg daily was associated with increased suicidality (91082).

Renal ...Data on the relationship between caffeine intake and kidney stones are conflicting. Some clinical research shows that caffeine consumption may increase the risk of stone formation (37634,111498), while other research shows a reduced risk with increasing caffeine intakes (111498). A meta-analysis of 7 studies found that overall, there is an inverse relationship, with a 32% decrease in the risk of kidney stones between the lowest and highest daily intakes of caffeine (111498).

Other ...People with voice disorders, singers, and other voice professionals are often advised against the use of caffeine; however, this recommendation has been based on anecdotal evidence. One small exploratory study suggests that caffeine ingestion may adversely affect subjective voice quality, although there appears to be significant intra-individual variability. Further study is necessary to confirm these preliminary findings (2724).

(Read more about CAFFEINE)

General ...Orally, capsicum is generally well tolerated in amounts typically found in food or when the extract is used in doses of up to 200 mg daily. Topically and intranasally, capsaicin, a constituent of capsicum, is generally well tolerated.
Most Common Adverse Effects:
Orally: Belching, bloating, burning, diarrhea, dyspepsia, gas, headache, mild constipation, nausea, rhinorrhea, skin flushing, and sweating.
Serious Adverse Effects (Rare):
Orally: Cases of myocardial infarction and hypertensive crisis have been reported.

Cardiovascular ...Orally, palpitation was reported in one clinical trial (105196).
One case of myocardial infarction has been reported in a 41-year-old male without cardiovascular risk factors; the event was attributed to the use of an oral capsicum pepper pill that the patient had been taking for weight loss (40768). Another case of coronary vasospasm and acute myocardial infarction has been reported for a healthy 29-year-old male; the event was attributed to the use of a topical capsicum-containing patch that the patient had been applying to the middle of the back for 6 days (40658). Two cases of arterial hypertensive crisis have been reported for individuals who ingested a large amount of peppers and chili peppers the day before. One of the patients also had an acute myocardial infarction, and the other had high levels of thyroid stimulating hormone (40569,40606).

Dermatologic ...Orally, capsicum or its constituent capsaicin may cause urticaria and skin wheals in rare cases (96457,105203).
Topically, capsicum can cause a prickling sensation, itching, pain, burning, edema, stinging, irritation, rash, and erythema. About 1 in 10 patients who use capsaicin topically discontinue treatment because of adverse effects. These effects seem to occur more often with topical formulations containing higher concentrations of capsaicin, the active constituent of capsicum. Side effects tend to diminish with continued use (12401,15260,15261,40358,40439,40483,40547,40676,40682,40719)(40784,40847,92979,92983,92984,96453,105193,105197,105202,111514). In one case, application of a capsaicin 8% patch (Qutenza) for 60 minutes caused a second-degree burn, characterized by burning, erythema, severe pain, and blistering at the administration site. The burn was treated with topical corticosteroids, but 9 months later neuropathic pain persisted, resulting in limited mobility. It is unclear whether the mobility sequalae were caused by topical capsaicin or the patient's pre-existing neurological disorders (111514). Skin contact with fresh capsicum fruit can also cause irritation or contact dermatitis (12408).
Intranasally, capsaicin can cause nasal burning and pain in most patients. It also often causes lacrimation, sneezing, and excessive nasal secretion; however, these side effects appear to diminish with repeat applications (14323,14329,14358). In some cases, the burning sensation disappears after 5-8 applications (14351,14358). In some cases, patients are pretreated with intranasal lidocaine to decrease the pain of intranasal capsaicin treatment. However, even with lidocaine pretreatment, patients seem to experience significant pain (14324).

Gastrointestinal ...Orally, capsicum can cause upper abdominal discomfort, including irritation, fullness, dyspepsia, gas, bloating, nausea, epigastric pain and burning, anal burning, diarrhea, mild constipation, and belching (12403,12410,40338,40427,40456,40503,40560,40584,40605,40665)(40718,40725,40745,40808,40828,96456,96457,105194,105196). There is a case report of a 3-year-old female who experienced a burning and swollen mouth and lips after touching the arm of a parent that had been treated with a capsaicin patch and then placing the fingers in the mouth (105199). Excessive amounts of capsaicin can lead to gastroenteritis and hepatic necrosis (12404). In a case report, a 40-year-old male with diabetes consumed white wine daily and chewed cayenne which was thought to result in black teeth stains and loss of enamel (40809). Some preliminary research links ingestion of capsaicin with stomach and gallbladder cancer; however the link may be due to contamination of capsaicin products with carcinogens (40771).
Topically, capsaicin can cause diarrhea and vomiting (105202).

Immunologic ...In a case report, a 34-year-old female had anaphylaxis involving difficulty breathing and stupor and also urticaria after consuming a red bell pepper, which is in the capsicum genus. The causal chemical was theorized to be 1,3-beta-glucanase (92978). In another case report, a 33-year-old female experienced angioedema, difficulty breathing and swallowing, and urticaria after ingesting raw green and red peppers (92982).

Neurologic/CNS ...Orally, capsicum can cause sweating and flushing of the head and neck, lacrimation, headache, faintness, and rhinorrhea (7005,12410,105196,105203). Topically, applying capsaicin can cause headache (96450,105202). Injection of capsaicin into the intermetatarsal space has also been associated with headache (96454).

Ocular/Otic ...Topically, capsicum can be extremely irritating to the eyes and mucous membranes. Capsicum oleoresin, an oily extract in pepper self-defense sprays, causes intense eye pain. It can also cause erythema, blepharospasm, tearing, shortness of breath, and blurred vision. In rare cases, corneal abrasions have occurred (12408,12409,40345,40348,40383,40720,40857).
Inhalation of capsicum can cause eye irritation, and allergic alveolitis (5885). In a case report, a 38-year-old female had acute anterior uveitis that developed about 12 hours after using a specific patch (Isola Capsicum N Plus) that contained capsaicin 1.5 mg per patch and methyl salicylate 132 mg per patch for neck pain. The uveitis was controlled with topical steroids and did not recur (92977).

Oncologic ...Population research suggests that moderate to high intake of capsaicin, the active constituent of capsicum, is associated with an increased risk of gastric cancer, while low intake is associated with a decreased risk. It is not clear from the study what amount of capsaicin is considered high versus low intake (92988). Additionally, some research suggests that any link may be due to contamination of capsaicin products with carcinogens (40771).

Pulmonary/Respiratory ...Orally, difficulty breathing was reported in a clinical trial (105196).
Topically, nasopharyngitis related to the use of a cream containing capsaicin has been reported (105202).
Inhalation of capsicum and exposure to capsicum oleoresin spray can cause cough, dyspnea, pain in the nasal passages, sneezing, rhinitis, and nasal congestion (5885,15016,40522,40546,40647). In rare cases, inhalation of the capsicum oleoresin or pepper spray has caused cyanosis, apnea, respiratory arrest and death in people. Death was caused by asphyxiation probably due to acute laryngeal edema and bronchoconstriction from inhalation of the capsicum oleoresin spray (40546,40672,40837,40879).
In a case report, a 47-year-old female who was exposed to capsaicin gas for more than 20 minutes experienced acute cough, shortness of breath, short-term chest pain, wheezing, and difficulty breathing for months afterwards (92980). In rare cases, exposure to capsicum oleoresin spray resulted in apnea, pulmonary injury, cyanosis, and even respiratory arrest (40383,40546).

(Read more about CAPSICUM)

General ...Orally and topically, no adverse effects have been reported. However, a thorough evaluation of safety outcomes has not been conducted.

(Read more about MARSHMALLOW)

General ...Information regarding the adverse effects of mullein is limited. A thorough evaluation of safety outcomes has not been conducted.

Dermatologic ...Two case reports have described dermatitis, with positive patch tests, after topical exposure to the whole plant, or by occupational inhalation of plant dust (92839,97316). In the case of topical exposure, the patient also had positive patch tests to other plants.

(Read more about MULLEIN)

General ...Orally, rutin is generally well tolerated.

Dermatologic ...Orally, rutin may cause flushing and rashes in some people (313).

Gastrointestinal ...Orally, rutin may cause gastrointestinal disturbance in some people (313).

Neurologic/CNS ...Orally, rutin may cause headache in some people (313).

(Read more about RUTIN)

General ...Orally, sweet clover is generally well tolerated when taken in small to moderate amounts. Topically or intravenously, no adverse effects have been reported. However, a thorough evaluation of safety outcomes has not been conducted for any use.
Serious Adverse Effects (Rare):
Orally: Large amounts have been reported to cause stupor and transient liver injury.

Hematologic ...A case of bleeding diathesis following ingestion of large amounts of a multi-herb, "seasonal tonic" tea made up of the coumarin-containing herbs sweet clover, sweet woodruff, and tonka bean for two months has been reported (809). It is unclear if this event is due to sweet clover, other ingredients, or the combination.

Hepatic ...Orally, large amounts of sweet clover can cause transient liver injury in susceptible individuals (18). A 23-year-old female with multiple sclerosis (MS) developed jaundiced palms and a slight elevation in serum alanine aminotransferase (ALT) without hyperbilirubinemia after taking a sweet clover supplement containing coumarin 10 mg daily (95166).

Neurologic/CNS ...Although rare, headache has been reported with oral use of sweet clover (1,2,18). Large amounts can cause stupor (18).

(Read more about SWEET CLOVER)