Complete Renewal by Adrian London

Alpha hydroxy acids represent a group of natural chemicals that are used alone or in combination. See specific monographs for effectiveness information.

(Read more about ALPHA HYDROXY ACIDS (AHAs))

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acne. Topical calendula has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research in patients with mild to moderate acne associated with mask wearing shows that topical application of a combination of calendula 4%, licorice root extract 0.3%, and snail secretion filtrate 40% (AI complex) to the face twice daily for 12 weeks modestly reduces inflammatory, but not non-inflammatory or total, acne lesions when compared with placebo. There was no difference in overall treatment success, defined as at least almost clear skin or a large improvement (110322). It is unclear if any benefits are due to calendula, other ingredients, or the combination.
• Bacterial vaginosis. It is unclear if topical calendula is beneficial for improving bacterial vaginosis. Details: A small clinical study in patients with bacterial vaginosis shows that applying 5 grams of vaginal cream containing calendula flower extract before bed for one week improves vaginal burning, odor, painful urination, and painful intercourse when compared to baseline (96649). The validity of these findings is limited by the lack of a comparator group.
• Burns. It is unclear if oral calendula is beneficial for burn healing. Details: A small clinical trial in patients hospitalized for second-degree burns shows that taking calendula 2 grams daily for 2 weeks has a large beneficial effect on wound healing when compared with placebo (110323).
• Chronic obstructive pulmonary disease (COPD). Oral calendula has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A small clinical study in males aged 40-70 years with a history of smoking and stage 2 COPD shows that taking a specific combination of calendula flowers 165 mg, elderberry 165 mg, and heart's ease herb 165 mg (Inflaminat, INAT-Farma), 3 capsules daily for 6 months, modestly improves symptoms, as measured on the breathlessness, cough, and sputum scale (BCSS), and mean forced expiratory volume in 1 second (FEV1) when compared to baseline. However, there was no improvement of COPD exacerbations or other pulmonary function tests (103629). The validity of this finding is limited by the lack of statistical comparison to the placebo group. Furthermore, it is unclear if these effects are due to calendula, the other ingredients, or the combination.
• Chronic prostatitis and chronic pelvic pain syndrome (CP/CPPS). Calendula in rectal suppositories has only been evaluated in combination with turmeric extract; its effect when used alone is unclear. Details: A small clinical study in patients with CP/CPPS shows that using a rectal suppository containing turmeric extract 350 mg and calendula extract 80 mg daily for one month improves pain, peak urine flow rate, and erectile function when compared with placebo (96648). It is unclear if these effects are due to calendula, turmeric, or the combination.
• Conjunctivitis. Although there is interest in using topical calendula for conjunctivitis, there is insufficient reliable information about the clinical effects of calendula for this condition.
• Diabetic foot ulcers. It is unclear if topical calendula is beneficial for improving diabetic foot ulcers. Details: Observational research has found that applying a calendula hydroglycolic extract spray in addition to standard care and hygiene is associated with reduced bacterial colonization and improved odor in patients that have had a diabetic ulcer for over 3 months (93548).
• Diaper rash. It is unclear if topical calendula is beneficial for improving diaper rash. Details: One preliminary clinical study in children less than 3 years of age shows that topical application of calendula 1.5% ointment three times daily for 10 days improves diaper rash when compared with aloe gel (19779). However, other preliminary clinical research shows that applying calendula 1.5% cream every 4-6 hours for 3 days improves diaper rash in fewer infants when compared to treatment with bentonite 50% mineral solution (93545,93554).
• Dysmenorrhea. Although there is interest in using oral calendula for dysmenorrhea, there is insufficient reliable information about the clinical effects of calendula for this condition.
• Gingivitis. It is unclear if using a mouth rinse with calendula is beneficial for improving gingivitis. Details: Preliminary clinical research in patients with mild gingivitis and bleeding gums shows that rinsing the mouth with a tincture containing calendula 25% (Dr. Willmar Schwabe Germany Home Pharmacy Pvt. Ltd.) twice daily for 6 months decreases plaque, gingivitis, and bleeding by 10% to 18% when compared to rinsing with water (93551). Other preliminary clinical research in adults with mild to moderate gingivitis and mild plaque shows that rinsing the mouth with a combination mouthwash containing a 5% extract of calendula, rosemary, and ginger for 30 seconds twice daily after food for 2 weeks decreases plaque, gingivitis, and bleeding when compared with a placebo mouthwash. The effects of this combination mouthwash appear to be similar to chlorhexidine 0.2% mouthwash (93555). It is unclear if these effects are due to calendula, other ingredients, or the combination.
• Hemorrhoids. Although there is interest in using topical calendula for hemorrhoids, there is insufficient reliable information about the clinical effects of calendula for this purpose.
• Liver disease. Although there is interest in using oral calendula for liver disease, there is insufficient reliable information about the clinical effects of calendula for this condition.
• Mosquito repellent. It is unclear if topical calendula essential oil helps to repel mosquitos. Details: Preliminary clinical research shows that applying calendula 50% essential oil to the skin does not repel mosquitos as effectively as applying DEET. Mean repellency time was about 2 hours for patients applying calendula, which was shorter than the 6 hour repellency with DEET (93562).
• Oral leukoplakia. It is unclear if topical calendula is beneficial for improving oral leukoplakia. Details: Preliminary clinical research in patients with oral leukoplakia shows that applying a gel containing calendula flower extract 0.2% three times daily for one month reduces lesion size by about 2 cm when compared to baseline (96650). The validity of this finding is limited by the lack of a comparator group.
• Oral mucositis. Calendula as a mouth rinse has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Clinical research in patients with head and neck cancer receiving chemotherapy and radiotherapy shows that rinsing with 7 mL of a specific product (Faringel, Cadigroup) containing calendula powder extract 2%, propolis, aloe vera, and chamomile three times daily for 6 weeks does not prevent oral mucositis when compared with placebo (95879).
• Otitis media. Topical calendula has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in children with otitis media shows that applying a specific combination product containing calendula, mullein, garlic, and St. John's wort in olive oil (Otikon Otic Solution, Healthy-On Ltd, Petach-Tikva, Israel), five drops into the affected ear three times daily for 3 days, may reduce ear pain when compared with baseline (39500,39552). It is unclear if this effect is due to calendula, other ingredients, or the combination. Furthermore, due to the lack of an adequate control group, it is unclear whether the pain reduction was due to the resolution of otitis media.
• Peptic ulcers. Although there is interest in using oral calendula for peptic ulcers, there is insufficient reliable information about the clinical effects of calendula for this condition.
• Pressure ulcers. It is unclear if topical calendula is beneficial for improving pressure ulcers. Details: Observational research has found that the application of a specific calendula product (Plenusdermax) twice daily is associated with improved healing in patients with pressure ulcers that have not changed in size for at least 3 months (93549). Preliminary clinical research in hospice patients with symptomatic pressure ulcers and other wounds shows that applying a homeopathic powder (RGN107) containing calendula 0.1% and arnica 0.01% to wounds for 4 weeks is rated by the patients and caregivers to be acceptable for controlling pain, odor, and exudate when compared with baseline (96647). The validity of this finding is limited by the lack of a control group.
• Radiation dermatitis. It is unclear if topical calendula reduces radiation dermatitis symptoms. Details: A meta-analysis of three preliminary clinical trials in patients with breast cancer shows that topical calendula does not affect the development of radiation dermatitis or the incidence of moderate to severe symptoms when compared to control (110325). In addition, a meta-analysis of two studies (39503,93560) shows that topical calendula does not reduce the incidence of treatment interruptions due to severe symptoms of radiation dermatitis (110325). In one of the included studies, a specific calendula petroleum jelly ointment (Pommade au Calendula par Digestion, Boiron Ltd.) used twice daily during radiation therapy was found to reduce acute radiation dermatitis occurrence when compared with topical trolamine (Biafine) (39503). However, it is unclear if the benefit was due to calendula or petroleum jelly. Another clinical study used a specific calendula 10% cream in wool fat and sesame oil (Calendula Weleda, Weleda AG) twice daily during radiation therapy. This product was found to be no better than aqueous petroleum jelly cream (Essex, Schering-Plough) for reducing acute skin reactions and dermatitis symptoms of pain, burning, itching, pulling, and tenderness (93560).
• Vaginal atrophy. Topical calendula has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in menopausal patients with vaginal atrophy shows that use of a specific vaginal gel containing calendula, Lactobacillus sporogenes, isoflavones, and lactic acid (Estromineral Gel, Rottapharm-Madaus) daily for 4 weeks reduces vaginal itching, burning, dryness, and painful intercourse when compared with no topical treatment. Both groups also received oral isoflavones (39534). It is unclear if these effects are due to calendula, other ingredients, or the combination.
• Vaginal candidiasis. One small clinical study suggest that topical calendula is not beneficial for the treatment of vaginal candidiasis. Details: Preliminary clinical research shows that applying 5 grams of calendula 1% cream intravaginally once daily for 7 days effectively treats vaginal candidiasis in 34% fewer patients when compared with using clotrimazole 1% cream (93559).
• Venous leg ulcers. It is unclear if topical calendula is beneficial for improving venous leg ulcers. Details: Preliminary clinical research shows that applying a calendula 7.5% ointment twice daily for 3 weeks to venous leg ulcers accelerates healing when compared with applying saline solution dressing (39509).
• Wound healing. It is unclear if topical calendula is beneficial for improving the healing of small wounds. Details: Two small clinical trials in postpartum patients show that applying calendula ointment (formulation unspecified) to the episiotomy wound every 8 hours for 5-10 days modestly reduces pain, and seems to speed up the resolution of redness, edema, and ecchymosis, when compared with standard care, such as application of betadine solution (93550,105087). Another small clinical study in adults with wounds smaller than 10 cm² on the hands and fingers shows that applying calendula flower extract 2% to the wound twice daily may modestly improve healing and epithelialization time when compared with mineral oil (107806). More evidence is needed to rate calendula for these uses.

(Read more about CALENDULA)

POSSIBLY INEFFECTIVE

• Human papillomavirus (HPV). Topical carrageenan gel does not seem to reduce the risk of anal HPV in males who have sex with males. Details: A clinical study in adult males who have sex with males shows that applying 15 mL of carrageenan 1.4% gel to the anus, condom, or partners' penis prior to receptive anal intercourse does not decrease the rate of anal HPV when compared with placebo, regardless of HPV strain, HPV vaccination status, or HIV status. Although patients were enrolled for an intended duration of 1 year, the study was terminated early due to a lack of observed benefit and potential safety concerns, resulting in a median follow-up of 8 months. A total of 60% of patients in the treatment group reported adverse effects, compared with 40% of patients in the placebo group (107851). Additionally, the prevalence of HPV at baseline was 61%, which may have reduced the study's ability to identify an effect.

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Common cold. Evidence on the use of intranasal iota-carrageenan for improving symptoms of the common cold is conflicting. Details: A small clinical study in patients with early symptoms of the common cold shows that spraying a saline solution containing iota-carrageenan 0.12% into the nose three times daily for 4 days seems to reduce total symptoms during days 2-4 when compared with using a plain saline spray. However, in a larger clinical trial using the same methods, there were no differences between placebo and treatment groups. Furthermore, neither study noted an improvement in total cold symptoms over 7-10 days (99449,99450). In children with the common cold, spraying a saline solution containing iota-carrageenan 0.12% seemed to be no better for improving cold symptoms than using plain saline spray (99451). Some research suggests that carrageenan might benefit patients with a confirmed viral infection. In a clinical study in patients with symptoms of a common cold and a laboratory-confirmed viral infection, using a specific nasal spray (Coldamaris) containing carrageenan 0.12% three times daily for 7 days reduced symptom duration by about 2 days when compared with using a saline nasal spray. However, there was no difference in disease duration when all patients were considered, regardless of viral infection status (99452). Furthermore, the validity of this study is limited by the changing definitions for disease duration and primary outcome over the course of the study.
• Coronavirus disease 2019 (COVID-19). There is limited evidence on the intranasal use of iota-carrageenan for the prevention of COVID-19. Details: A clinical study in healthcare professionals working with patients hospitalized for COVID-19 shows that using a nasal spray containing iota-carrageenan 0.17% as 1 puff in each nostril 4 times daily (providing 1 mg daily) for 21 days decreases the absolute rate of confirmed, symptomatic COVID-19 to 1%, compared with 5% of patients in the placebo group. This suggests that 25 people would need to use this nasal spray to prevent one infection (107852). The validity of this study is limited due to the lack of baseline viral testing and short duration; additionally, asymptomatic COVID-19 infections may be underreported due to study design.
• Cough. Although there is interest in using oral carrageenan for cough, there is insufficient reliable information about the clinical effects of carrageenan for this condition. More evidence is needed to rate the effectiveness of carrageenan for these uses.

(Read more about CARRAGEENAN)

LIKELY EFFECTIVE

• Constipation. Rectal glycerol is beneficial in children and adults with constipation. Details: Glycerol rectal suppositories and enemas are approved by the US Food and Drug Administration (FDA) for over-the-counter use to treat occasional constipation in adults and children at least 2 years of age (15).

POSSIBLY EFFECTIVE

• Athletic performance. Oral glycerol may improve hydration during exercise, but clinical studies evaluating glycerol for improving measures of athletic performance are limited and conflicting. Details: Several clinical studies show that glycerol increases serum osmolality and improves hydration status during exercise (2475,2476,93757,93760,93761,93765). One meta-analysis, including 14 studies and 99 patients, shows that glycerol-induced hyperhydration increases body water by approximately 2.5-fold when compared with water-induced hyperhydration (93757). Also, taking glycerol along with table salt 7.5 grams per liter fluid seems to improve hydration status when compared withg glycerol alone (99162). Research regarding the effects of glycerol on thirst, comfort, temperature regulation, sweating, and heart rate is conflicting (2475,2476,93760,99162). While glycerol may improve hydration status during exercise, it is unclear whether it can improve measures of athletic performance. An early meta-analysis including a total of 36 athletes shows that taking glycerol increases endurance performance by 2.6%. Although this is a small difference, it might be considered meaningful to athletes (93757). Some small clinical studies in athletes suggest that glycerol increases endurance and time to exhaustion, with no effect on heat regulation (2475,2479,93764). However, other small studies suggest that glycerol does not reduce perceived exhaustion or improve exercise performance (2476,93760). Also, glycerol has not been shown to increase time to exhaustion in triathletes (2492). When used to improve athletic performance, glycerol is most often taken at doses of 1-1.5 gram/kg in conjunction with approximately 1.5 L of fluid, 60-120 minutes before competition, and in some cases continued during the competition (2475,93757,93760,93764).
• Ichthyosis. Topical application of a specific product containing glycerol and paraffin may improve symptoms of ichthyosis in children. The benefits of topical glycerol alone in these patients is unknown. Details: A large clinical trial in children aged 1 month to 18 years shows that applying a specific product (Dexeryl, Pierre Fabre Laboratoires) containing glycerol 15% and paraffin 10% for 4 weeks reduces symptoms of non-bullous ichthyosis by at least 50% in an additional 17% of children when compared with a placebo cream. Applying this specific product also improves pruritus by an additional 45% when compared with placebo (93756). It is unclear if these findings are due to glycerol, paraffin, or the combination.

POSSIBLY INEFFECTIVE

• Meningitis. Some clinical research suggests that oral glycerol does not reduce the risk of mortality or seizures in adults and children with bacterial meningitis, although it may reduce certain sequelae. Details: A meta-analysis of five low-quality clinical trials including 1,270 patients shows that adjunctive treatment with glycerol as an oral osmotic agent does not reduce the risk of mortality, seizures, or gastrointestinal symptoms in adults and children with acute bacterial meningitis, although it may modestly reduce the risk of deafness and residual neurological deficit in surviving children (99160). Clinical research included in the meta-analysis has used glycerol 1.5 grams/kg every 6 hours in children aged 2 months to 16 years (93762,93763).
• Prematurity. Rectal glycerol does not appear to reduce the time to enteral feeding in premature infants. Details: Glycerol is used as an enema or given by suppository to facilitate the evacuation of meconium in premature infants in order to reduce the time to enteral feeding. However, two meta-analyses of small studies in preterm infants, that include some of the same studies, show that administering glycerol suppositories does not reduce the number of days to full enteral feeds when compared with placebo or no treatment (99166,112003). However, the interpretation of these findings is limited by the heterogeneity of dosages used in the included studies.

LIKELY INEFFECTIVE

• Stroke. Intravenous glycerol may not improve mortality or symptoms in patients with acute ischemic stroke. Details: Several clinical studies show that intravenous administration of glycerol does not improve symptoms of acute stroke (2480,2481,2482,2484,2486). Additionally, one clinical study in elderly patients with acute ischemic stroke shows that while glycerol can improve initial survival, it does not reduce the risk of overall mortality when compared with placebo (2483).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Dandruff. Topical glycerol has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One clinical trial in adults with dandruff shows that applying a leave-in hair lotion containing glycerol 10%, stearic acid 2.5%, and sunflower seed oil 0.6%, 3 times weekly for 8 weeks, modestly reduces dandruff severity throughout use and for up to one week after the last application when compared with a placebo lotion. The glycerol lotion also reduced total water loss from the scalp by 8% and increased moisturization by 23% (93758). It is unclear if these findings are due to glycerol, other ingredients, or the combination.
• Dry skin. Topical glycerol has only been evaluated in combination with other ingredients for the management of dry skin associated with kidney failure; its effect when used alone is unclear. Details: One small, open-label clinical study in adults with kidney failure and moderate to severe uremic xerosis shows that applying an emulsion containing glycerol 15% and paraffin 10% twice daily for 7 days reduces the severity of xerosis when compared with a placebo emulsion. The glycerol-containing emulsion produces a treatment response in an additional 29% of patients, improves quality of life, and reduces scale density and thickness when compared with placebo (93754). It is unclear if these findings are due to glycerol, paraffin, or the combination.
• Glaucoma. Although there has been interest in using oral glycerol for glaucoma, there is insufficient reliable information about the clinical effects of glycerol for this purpose.
• Intracranial hypertension. Although there has been interest in using intravenous glycerol to reduce intracranial pressure in patients with brain tumors, central nervous system (CNS) trauma, encephalitis, idiopathic intracranial hypertension, meningitis, and Reye syndrome, there is insufficient reliable information about the clinical effects of glycerol for this purpose.
• Meniere disease. It is unclear if intravenous glycerol is beneficial in patients with Meniere disease. Details: A small, uncontrolled clinical study in adults with unilateral, intractable Meniere disease shows that intravenous administration of glycerol 10% at a dose of 0.5 grams/kg once daily for 2 consecutive days, twice monthly for 6 months, reduces the frequency of vertigo attacks and improves quality of life when compared to baseline. Patients reported an average of 3.2 vertigo attacks per month at baseline and 1.2 vertigo attacks per month after 6 months of treatment (106649). The lack of a control group limits the validity of these findings.
• Neonatal jaundice. It is unclear if rectal glycerol improves jaundice-related outcomes in premature infants. Details: A small clinical study in neonates receiving phototherapy for jaundice shows that administering glycerol suppositories has no effect on the duration of phototherapy needed for jaundice treatment, or on bilirubin levels or the rate of bilirubin decline when compared with no glycerol suppositories (99165).
• Obesity. It is unclear if oral glycerol is beneficial in patients who are overweight or obese. Details: One small clinical study in adults on a low-calorie diet shows that taking glycerol 7.5 grams before meals for 6 weeks does not increase weight loss when compared with placebo (2485).
• Otitis externa. Topical glycerol has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: One small clinical study in adults with otitis externa shows that inserting ribbon gauze soaked in glycerol and ichthammol into the ear canal reduces pain and swelling as effectively as the application of antibiotic and steroid drops three times daily (93759). It is unclear if these findings are due to glycerol, ichthammol, or the combination. More evidence is needed to rate glycerol for these uses.

(Read more about GLYCEROL)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Acne. Although there has been interest in using topical grapefruit oil for acne, there is insufficient reliable information about the clinical effects of grapefruit for this purpose.
• Asthma. It is unclear if oral grapefruit is beneficial in patients with asthma. Details: There is some evidence that consumption of vitamin C-rich citrus fruits, including grapefruit and others, might improve lung function in people with asthma. Intake of citrus fruits 1-2 times weekly has produced this benefit in some studies (6049,6055,6056). However, other studies have shown no benefit (6057,6058).
• Atherosclerosis. Although there has been interest in using oral grapefruit to treat or prevent atherosclerosis, there is insufficient reliable information about the clinical effects of grapefruit for this purpose.
• Atopic dermatitis (eczema). It is unclear if oral grapefruit seed extract is beneficial in patients with atopic dermatitis. Details: One small, uncontrolled clinical study in patients with atopic dermatitis shows that taking a specific grapefruit seed extract product (ParaMicrocidin, Allergy Research Group) 150 mg three times daily for one month can decrease complaints of constipation, flatulence, and abdominal discomfort, possibly due to changes in intestinal microflora (5866). The validity of these findings is limited by a lack of control group.
• Depression. Although there has been interest in using inhaled grapefruit oil as aromatherapy for depression, there is insufficient reliable information about the clinical effects of grapefruit oil for this purpose.
• Gingivitis. Although there has been interest in using topical grapefruit oil as a rinse for gingivitis, there is insufficient reliable information about the clinical effects of grapefruit oil for this purpose.
• Headache. Although there has been interest in using inhaled grapefruit oil as aromatherapy for headache, there is insufficient reliable information about the clinical effects of grapefruit oil for this purpose.
• Hypercholesterolemia. It is unclear if oral grapefruit is beneficial in patients with hypercholesterolemia. Details: One small clinical study in patients with hypercholesterolemia shows that taking capsules containing grapefruit pectin 5 grams three times daily for 16 weeks decreases total cholesterol by 8% and the ratio of low-density lipoprotein (LDL) to high-density lipoprotein (HDL) cholesterol by 10% when compared to baseline (2216). The validity of these findings is limited by the lack of a comparator group.
• Hypertriglyceridemia. It is unclear if oral grapefruit is beneficial in patients with hypertriglyceridemia. Details: One small clinical study in patients with hypertriglyceridemia that is not well controlled on statin therapy shows that consuming one red or white grapefruit daily for 30 days reduces total cholesterol by 8% to 15.5% and low-density lipoprotein (LDL) cholesterol by 11% to 20% when compared with placebo. In addition, consuming one red, but not one white, grapefruit daily reduces triglyceride levels by 17% when compared with placebo in these patients (53352).
• Intestinal parasite infection. Although there has been interest in using oral grapefruit seed extract for intestinal parasite infections, there is insufficient reliable information about the clinical effects of grapefruit for this purpose.
• Lice. It is unclear if topical grapefruit extract is beneficial in children with head lice. Details: One small clinical study in children aged 2-9 years with head lice shows that applying 50 mL of a specific shampoo containing grapefruit extract (Licatack shampoo) to the hair for 10-20 minutes and then rinsing with water and combing can eliminate adult lice. Applying a second application after 10 days seems to help remove any remaining nits (91417). The validity of these findings is limited by a lack of control group.
• Obesity. While some small studies suggest that oral grapefruit extract, taken in combination with other citrus extracts, may modestly improve weight loss, the effect of oral grapefruit alone is unclear. Details: One small clinical study in obese adults shows that consuming one and a half fresh grapefruits daily for 12 weeks reduces body weight by 1.3 kg when compared with placebo. Also, although drinking 8 ounces of grapefruit juice or taking grapefruit capsules three times daily for 12 weeks did not improve body weight when compared with placebo in the overall study population, a sub-group analysis of obese adults with metabolic syndrome shows that taking grapefruit capsules or drinking grapefruit juice increases weight loss and improves insulin resistance when compared with placebo (53353). Grapefruit has also been evaluated in combination with other citrus ingredients. Two clinical studies shows that taking a specific combination product (Sinetrol, Fytexia) containing sweet orange, blood orange, and grapefruit extracts for 12 weeks can decrease body weight, body fat percentage, and body mass index (BMI) in otherwise healthy overweight adults (95517,95518). In one study, taking this supplement as 450 mg twice daily for 12 weeks reduced body weight by 1 kg and body fat percentage by 6.5% when compared with placebo. Hip circumference, waist circumference, and blood glucose were also reduced when compared with placebo (95518). In another study, taking this same supplement as 700 mg twice daily for 12 weeks reduced body weight by 5.6 kg, body fat percentage by 5%, and BMI by 2% when compared to baseline. Patients taking placebo experienced no significant improvements from baseline (95517). It is not clear if these effects are due to grapefruit extract, other ingredients, or the combination.
• Pharyngitis. Although there has been interest in using topical grapefruit oil as a gargle for pharyngitis, there is insufficient reliable information about the clinical effects of grapefruit oil for this purpose.
• Psoriasis. Although there has been interest in using oral grapefruit for psoriasis, there is insufficient reliable information about the clinical effects of grapefruit for this purpose.
• Stress. Although there has been interest in using inhaled grapefruit oil as aromatherapy for stress, there is insufficient reliable information about the clinical effects of grapefruit oil for this purpose.
• Upper respiratory tract infection (URTI). Although there has been interest in using grapefruit oil as aromatherapy for various upper respiratory tract infections, including influenza and the common cold, there is insufficient reliable information about the clinical effects of grapefruit oil for these conditions.
• Vaginal candidiasis. Although there has been interest in using oral and topical grapefruit seed extract for vaginal candidiasis, there is insufficient reliable information about the clinical effects of grapefruit seed extract for this purpose. More evidence is needed to rate grapefruit for these uses.

(Read more about GRAPEFRUIT)

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Allergic rhinitis (hay fever). Lemon has only been evaluated in combination with quince in a nasal spray for hay fever; its effect when used alone is unclear. Details: A small clinical study in patients with grass pollen allergy shows that using a specific nasal spray (Gencydo, Weleda AG) containing lemon and quince three times daily for 7 days does not improve the symptoms of allergic rhinitis when compared with placebo. In this study, using the nasal spray reduced airway resistance during inspiration at 10 and 20 minutes after pollen exposure, and reduced airway resistance during expiration at 20 minutes after pollen exposure (98826).
• Anxiety. It is unclear if aromatherapy with lemon essential oil reduces test anxiety. Details: A small clinical study in first year nursing students in Turkey shows that administering aromatherapy with lemon essential oil for 15 minutes prior to an exam reduces test anxiety scores when compared with control students (110779). However, it is unclear whether any improvements are clinically significant or lead to improved test scores.
• Halitosis. Lemon essential oil has only been evaluated in combination with other essential oils; its effect when used alone is unclear. Details: Preliminary research in males with dementia in a long-term care facility shows that cleaning the tongue, gums, and teeth with a solution of lemon, peppermint, and tea tree essential oils twice daily for 7 days improves oral condition, measured on the Korean Oral Assessment Guide scale, increases salivary pH into the normal range, and decreases halitosis score when compared with saline control. On a scale of 0 to 5, the essential oil mixture reduced the halitosis score by 1.24 points, compared with 0.2 points for the control (112957).
• Hypertension. It is unclear if oral lemon is beneficial in patients with high blood pressure. Details: A small, prospective, population study in middle-aged Japanese women has found that increased lemon intake is associated with a modest reduction in systolic, but not diastolic, blood pressure (93471).
• Kidney stones (nephrolithiasis). It is unclear if oral lemon juice is beneficial for recurrent idiopathic calcium oxalate nephrolithiasis. Details: A randomized, controlled trial in patients with recurrent idiopathic calcium oxalate nephrolithiasis shows that taking fresh lemon juice 60 mL orally twice daily for 2 years with a standard diet does not improve the time to stone recurrence when compared with no supplementation. The validity of these findings is limited due to poor patient adherence, which declined from 79% at 6 months, to 68% at 1 year, and 48% at 2 years. When restricted to a 1-year follow-up, stone recurrence occurred in 10% of patients taking lemon juice, compared with 21% of patients in the control group; this difference was statistically significant (107489).
• Meniere disease. Although there is interest in using lemon orally for Meniere disease, there is insufficient reliable information about the clinical effects of lemon for this condition.
• Myocardial infarction (MI). It is unclear if aromatherapy with lemon essential oil is beneficial in patients with acute MI. Details: A small clinical study in hospitalized patients with acute MI shows that administering aromatherapy with lemon essential oil over 3 days moderately reduces systolic blood pressure, but not diastolic blood pressure, when compared with a paraffin control. Heart rate and anxiety were reduced by a small amount the day following the completion of lemon aromatherapy (103455).
• Nausea and vomiting. It is unclear if aromatherapy with lemon oil is beneficial in palliative care patients with nausea and vomiting. Details: A small observational study in hospitalized palliative care patients with advanced cancer has found that administering aromatherapy with lemon oil pads relieves nausea and vomiting in 73% of applications (110778). The interpretation of these findings is limited by the use of a retrospective chart review and the lack of a comparator group.
• Obesity. Although there is interest in using lemon orally for obesity, there is insufficient reliable information about the clinical effects of lemon for this condition.
• Oral mucositis. Lemon has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A randomized, controlled trial in patients with head and neck cancer receiving external beam radiotherapy 5 days weekly shows that using a 2:1 oral honey-lemon throat spray four to eight times daily, beginning 1 day prior to radiotherapy initiation and continuing for 5 weeks, does not improve severity of mucositis when compared with oral benzydamine hydrochloride throat spray applied four to eight times daily. The actual rate of oral mucositis occurrence is 65% in those receiving the honey-lemon spray, compared with 35% with the benzydamine hydrochloride spray; however, this difference was not statistically significant (107487). This study may have been inadequately powered to detect a difference between groups. Also, the validity of these findings is limited due to the lack of objective outcome measures.
• Postoperative nausea and vomiting (PONV). It is unclear if aromatherapy with lemon essential oil is beneficial in patients with PONV. Details: Preliminary research in patients undergoing lower extremity fracture surgery shows that aromatherapy with lemon essential oil started the morning of surgery, then every 2 hours to the end of surgery, in the recovery room, and 16 hours after surgery reduces the frequency, severity, and amount of PONV, and the frequency of anti-emetic drug administration after surgery, when compared with control. The intensity of pain is also reduced, but not the amount of post-operative opioid needed (112956).
• Pregnancy-induced nausea and vomiting. It is unclear if aromatherapy with lemon essential oil is beneficial in patients with nausea and vomiting due to pregnancy. Details: A small clinical study in pregnant patients shows that practicing aromatherapy with 2 drops of lemon essential oil placed on a cotton ball as needed modestly reduces pregnancy-induced nausea and vomiting on 2 of 4 days of the study when compared with placebo (93475).
• Radiation-induced sialadenitis. Aromatherapy with lemon essential oil has only been evaluated in combination with other essential oils; its effect when used alone is unclear. Details: A small clinical study in patients with thyroid cancer shows that receiving 10-minute aromatherapy baths with lemon and ginger essential oils prior to meals for 2 weeks before treatment with radioactive iodine therapy attenuates damage to the salivary gland when compared with distilled water baths (98129).
• Respiratory tract infections. Although there is interest in using lemon orally for respiratory tract infections such as cold and flu, there is insufficient reliable information about the clinical effects of lemon for these conditions. More evidence is needed to rate lemon for these uses.

(Read more about LEMON)

POSSIBLY EFFECTIVE

• Osteoarthritis. When used alone or in combination with other ingredients, oral rose hip seems to reduce pain and improve function in patients with osteoarthritis. Details: Orally, rose hip seems to have beneficial effects when used to treat osteoarthritis. Most clinical research shows that taking a specific Rosa canina rose hip powder product (LitoZin/i-flex, Hyben Vital), 2.5 grams orally twice daily for 3-4 months, reduces pain and stiffness, improves function and mobility, and decreases use of rescue medication when compared with placebo (71646,71658,71660,71661). Clinical research in adults with knee osteoarthritis shows that taking a specific combination product containing Rosa canina rose hip fruit puree 24 grams, stinging nettle leaf 160 mg, devil's claw 108 mg, and vitamin D 200 IU (Rosaxan, Medagil Gesundheitsgesellschaft) daily for 12 weeks reduces pain by 66% and improves quality of life, but does not reduce analgesic use, when compared with a control group (97937). However, one crossover study shows mixed results. Rose hip was shown to be effective for osteoarthritis only when administered after, but not before, placebo treatment (71641). This inconsistency might be due to a carryover effect of rose hip or delayed activity of the supplement.
• Postoperative pain. When taken immediately prior to surgery, oral rose hip seems to reduce pain following a Cesarean section. Details: Clinical research shows that taking a single dose of Rosa damascena rose hip extract 1600 mg, 15 minutes prior to anesthesia for a Cesarean section, delays the need for postoperative analgesics and reduces their use over the next 24 hours when compared with placebo. Almost all patients taking placebo requested analgesics within 2 hours of surgery, compared with only 11% of those taking rose hip extract. In addition, this rose hip extract moderately reduced the level of pain over the 24-hour period (104556).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Aging skin. It is unclear if oral rose hip is beneficial for improving wrinkles. Details: Preliminary clinical research shows that taking Rosa canina rose hip powder (Hyben Vital) 1.5 grams twice daily for 8 weeks improves wrinkles, skin moisture, and elasticity when compared with baseline. However, it is unclear if these benefits are clinically significant (104557). Also, the validity of these findings is limited by the lack of a comparator group.
• Benign prostatic hyperplasia (BPH). Although there has been interest in using oral rose hip for BPH, there is insufficient reliable information about the clinical effects of rose hip for this condition.
• Cancer. Although there has been interest in using oral rose hip for cancer, there is insufficient reliable information about the clinical effects of rose hip for this condition.
• Common cold. Although there has been interest in using oral rose hip for the common cold, there is insufficient reliable information about the clinical effects of rose hip for this condition.
• Diabetes. Although there has been interest in using oral rose hip for diabetes, there is insufficient reliable information about the clinical effects of rose hip for this condition.
• Dysmenorrhea. It is unclear if oral rose hip is beneficial for reducing menstrual pain. Details: Preliminary clinical research shows that taking Rosa damascena rose hip extract 200 mg every 6 hours for 3 days is as effective as taking mefenamic acid 250 mg on the same dosing schedule for reducing pain associated with dysmenorrhea (104555).
• Gout. Although there has been interest in using oral rose hip for gout, there is insufficient reliable information about the clinical effects of rose hip for this condition.
• Hyperlipidemia. Although there has been interest in using oral rose hip for hyperlipidemia, there is insufficient reliable information about the clinical effects of rose hip for this condition.
• Hypertension. Although there has been interest in using oral rose hip for hypertension, there is insufficient reliable information about the clinical effects of rose hip for this condition.
• Influenza. Although there has been interest in using oral rose hip for influenza, there is insufficient reliable information about the clinical effects of rose hip for this condition.
• Obesity. It is unclear if oral rose hip is beneficial for obesity. Details: Preliminary clinical research shows that taking Rosa canina rose hip powder 40 grams daily mixed with apple juice for 6 weeks does not significantly affect weight or glucose tolerance when compared with placebo. However, it decreases total cholesterol by 5%, low-density lipoprotein (LDL) cholesterol by 6%, and systolic blood pressure by 4% when compared with placebo (18104).
• Rheumatoid arthritis (RA). It is unclear if oral rose hip is beneficial for RA. Details: Preliminary clinical research in adults with RA shows that taking a specific Rosa canina rose hip powder product (LitoZin/i-flex, Hyben Vital) 2.5 grams (5 capsules) twice daily over 6 months improves patient scores on a disability index, as well as other subjective physician- and patient-based assessments, when compared with placebo (17416).
• Sciatica. Although there has been interest in using oral rose hip for sciatica, there is insufficient reliable information about the clinical effects of rose hip for this condition.
• Sexual dysfunction. Oral rose hip has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research in women with sexual dysfunction shows that taking a specific combination tablet (Lady Prelox, Horphag Research) containing a standardized extract of rose hip (Rosvita) 50 mg, maritime pine bark (Pycnogenol, Horphag Research) 20 mg, L-arginine 200 mg, and L-citrulline 200 mg orally daily for 8 weeks, in combination with a management program consisting of lifestyle, diet, exercise, and stress control changes, improves overall sexual function when compared with the management program alone (91963). Taking the same product in a dose of 2 tablets twice daily for 8 weeks, in addition to the lifestyle management program, improves vaginal dryness in pre- and post-menopausal women when compared with lifestyle management alone (103611). The effect of rose hip extract alone on sexual dysfunction is unclear.
• Stretch marks (striae gravidarum). Topical rose hip 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 formulation containing hydroxyprolisilane C, rose hip oil, gotu kola triterpenes, and vitamin E (Velastisa Antiestrías, ISDIN) twice daily during pregnancy, beginning at week 10-14 and continuing throughout pregnancy, decreases the severity of both new and old stretch marks when compared with placebo. It also appears to decrease the incidence of stretch marks by about 84% in women without previous striae (92507).
• Urinary tract infections (UTIs). It is unclear if oral rose hip is beneficial for UTI prevention. Details: Preliminary clinical research in women who have undergone a Cesarean section shows that taking Rosa canina rose hip powder 500 mg twice daily, starting 2 days post-partum and continuing for 20 days, reduces the odds of asymptomatic, culture-positive UTIs by 68% when compared with placebo. However, rose hip does not appear to reduce the incidence of symptomatic UTIs in these patients (97938).
• Vitamin C deficiency. Although there has been interest in using oral rose hip for vitamin C deficiency, there is insufficient reliable information about the clinical effects of rose hip for this condition. More evidence is needed to rate rose hip for these uses.

(Read more about ROSE HIP)

POSSIBLY EFFECTIVE

• Coronary heart disease (CHD). The U.S. Food and Drug Administration (FDA) allows a qualified health claim stating that using high-oleic acid sunflower oil as a replacement for other dietary fats and oils higher in saturated fat may reduce the risk of CHD. Details: A meta-analysis of clinical studies shows that replacing 7.5% of energy from partially hydrogenated vegetable oils with high-oleic acid sunflower oil can reduce CHD risk by about 9% to 19%. Furthermore, analysis of results from observational studies found that replacing partially hydrogenated oil with high-oleic acid sunflower oil is associated with a 16% to 35% reduction in the risk of CHD events (95745). The FDA allows for a qualified health claim that replacing dietary fats and oils higher in saturated fat with high-oleic acid sunflower oil may reduce the risk of CHD. To achieve this benefit, the use of high-oleic acid sunflower oil should not increase total daily energy intake. The suggested daily dietary intake is about 20 grams (1.5 tbsp) of high-oleic sunflower oil in place of other fats and oils (98563). Sunflower oil that contains high amounts of linoleic acid rather than oleic acid does not appear to improve cholesterol levels or reduce the risk of cardiovascular events in patients with CHD (96205).
• Hypercholesterolemia. Consuming sunflower oil in the diet may reduce low-density lipoprotein (LDL) cholesterol levels in some patients. Details: There is evidence that using sunflower oil in the diet as 45-50 grams daily for up to 12 weeks is more effective than olive oil for decreasing LDL cholesterol and apolipoprotein B levels in healthy individuals (9780). Also, clinical research in patients with mild hyperlipidemia or moderate hypercholesterolemia shows that consuming specific brands of mid-oleic acid (NuSun) or high-oleic acid (Sunola, Meadow Lea Foods) sunflower oils as 15% to 20% of dietary calories for up to 5 weeks is more effective than olive oil or saturated fat for decreasing total cholesterol, LDL cholesterol, and apolipoprotein B levels (76697,76698). Also, consuming a high-oleic sunflower oil-rich diet for 3 weeks decreases total cholesterol levels to a greater extent than diets enriched with palm oil or medium-chain triglycerides in patients with mild hypercholesterolemia (67569). Other preliminary clinical research in patients with moderate hypercholesterolemia shows that consuming a diet rich in sunflower oil for 3 weeks decreases total cholesterol and LDL cholesterol levels when compared with baseline. However, levels of high-density lipoprotein (HDL) cholesterol appear to be lowered as well (76714). Despite these beneficial effects, sunflower oil might be less effective than some other dietary oils. Taking sunflower oil for 3 months appears to be less effective than rice bran oil for lowering cholesterol in patients with hypercholesterolemia (76699). Also, while consuming sunflower oil 45 grams daily, as part of the diet and as a supplement, for 12 weeks reduces levels of total cholesterol and LDL cholesterol when compared to baseline, it appears to be less effective at reducing total cholesterol levels than flaxseed oil in certain patients at risk for atherosclerosis (76696). In addition, taking sunflower oil 15.1 grams daily for 4 months does not appear to reduce levels of total or LDL cholesterol in patients with peripheral vascular disease (76691).

POSSIBLY INEFFECTIVE

• Hypertension. Oral sunflower oil does not seem to lower blood pressure. Details: Preliminary clinical research in adults with hypertension shows that taking sunflower oil 30-40 grams daily for one year is less effective than extra-virgin olive oil for reducing blood pressure (5091). Also, clinical research in elderly adults with hypertension shows that taking 60 grams of sunflower oil daily for 4 weeks is less effective than virgin olive oil for reducing systolic blood pressure (76692).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Atherosclerosis. It is unclear if oral sunflower oil is beneficial for atherosclerosis; some clinical research suggests that it may provide less benefit than other dietary oils. Details: Some preliminary clinical research in individuals with overweight and obesity shows that taking sunflower oil 30 mL (about 27 grams) daily for 90 days decreases carotid intima-media thickness (CIMT) by 3.5% when compared to baseline, but not when compared with olive oil or flaxseed oil. Sunflower oil also improves flow-mediated vasodilation by 73% when compared to baseline, compared with no improvement in those taking flaxseed oil or olive oil (99303). Other preliminary clinical research in individuals waiting for carotid endarterectomy shows that taking sunflower oil 6 grams daily for up to 189 days is less effective than the same dose of fish oil, and equivalent to control oil, for improving the status of atherosclerotic plaques (76688).
• Atopic dermatitis (eczema). Although there is interest in using topical sunflower oil for atopic dermatitis, there is insufficient reliable information about the clinical effects of sunflower oil for this condition.
• Child growth. It is unclear if topical sunflower oil is beneficial for early child growth. Details: A large preliminary clinical trial in newborn infants in India shows that exclusive topical application of 10 mL of high-linoleic acid sunflower oil, an average of 2.7 times daily for about one month, increases weight gain by 1.3 gram/kg daily when compared with a control group exclusively given traditional vigorous massage with mustard oil an average of 2.4 times daily. The increase in weight gain was highest for infants weighing less than 1500-2000 grams at birth (108141). However, it is unclear if any beneficial effects are due to the sunflower oil, the massage, their combination, or the lack of mustard oil.
• Dry mouth. It is unclear if rinsing the mouth with sunflower oil is beneficial for dry mouth. Details: Preliminary clinical research in adults with moderate dry mouth associated with medication use shows that using a sunflower oil mouth rinse and gargling for 5-8 minutes before spitting it out twice daily for 7 days improves dry mouth scores by 23% when compared to baseline. Sunflower oil also improves the ability to swallow and sleep with dry mouth, but not other dry mouth symptoms or saliva flow rate, when compared with control (105523). This study may have been inadequately powered to detect a difference between groups.
• Dry skin. It is unclear if topical sunflower oil is beneficial for dry skin in infants. Details: Preliminary clinical research in full-term, newborn infants shows that topical application of 4 drops of sunflower oil to each of three parts of the body twice daily for 4 weeks improves skin hydration, but not skin barrier function or the presence of redness or rash, when compared with not using topical oil. Furthermore, use of sunflower oil may impede the normal development of skin barrier function that occurs during the first four weeks of life (96144).
• Fetal and premature infant mortality. It is unclear if topical sunflower oil is beneficial for preventing early mortality in premature infants. Details: A large clinical trial in newborn infants in India shows that exclusive topical application of 10 mL of high-linoleic acid sunflower oil, an average of 2.7 times daily for about one month, reduces infant mortality by 58% when compared to a control group exclusively given traditional vigorous massage with mustard oil an average of 2.4 times daily. A subgroup analysis of premature infants also shows a 52% reduction in mortality with the use of high-linoleic acid sunflower oil when compared with control (108143). However, it is unclear if any beneficial effects are due to the sunflower oil, the massage, their combination, or the lack of mustard oil.
• Prematurity. Small to moderate-sized clinical studies suggest that topical sunflower oil might increase body weight, reduce length of hospital stay, and improve skin hydration and skin integrity in preterm neonates. Details: Preliminary clinical research in preterm infants with low birth weight shows that massaging for 5-10 minutes using sunflower oil 10 mL/kg three times daily for 2 weeks increases weight gain by approximately 35% over 2 months when compared with massage using no oil. Sunflower oil massage does not appear to increase length or head circumference (96145). A small clinical study in premature infants in the intensive care unit (ICU) shows that a similar massage with sunflower oil three times daily for 5 days shortens ICU stay by about 5 days when compared with no massage. Furthermore, over the ICU stay, infants in the sunflower oil massage group gained an average of 15 grams, whereas infants in the control group experienced weight loss (98479). The effect of sunflower oil on skin hydration and integrity in preterm infants has also been assessed. A clinical trial of 90 preterm infants in a Turkish neonatal ICU shows that whole body skin treatment (not massage) with either sunflower oil or almond oil 4 mL/kg four times daily for 5 days improves measures of skin hydration and skin integrity when compared with control infants that did not receive oil treatment. The sunflower and almond oil treatments are equally effective (105524). Another clinical study in 90 infants (42% preterm) in a Turkish neonatal ICU shows that whole body skin treatment (not massage) with sunflower oil or liquid Vaseline 3-4 mL for preterm and 5-6 mL for full-term infants daily for 16 days improves measures of skin integrity when compared with control infants that did not receive any oil treatment. Skin integrity scores were better in the sunflower oil group than liquid Vaseline at some time points (111726).
• Psoriasis. Although there is interest in using topical sunflower oil for psoriasis, there is insufficient reliable information about the clinical effects of sunflower oil for this condition.
• Rheumatoid arthritis (RA). Although there is interest in using oral sunflower oil for RA, there is insufficient reliable information about the clinical effects of sunflower oil for this condition.
• Tinea pedis. It is unclear if topical sunflower oil is beneficial for tinea pedis. Details: Preliminary clinical research shows that topical application of a specific brand of ozonized sunflower oil (Oleozon) twice daily for 6 weeks is as effective as ketoconazole for curing athlete's foot (76687). More evidence is needed to rate sunflower oil for these uses.

(Read more about SUNFLOWER OIL)

Some alpha hydroxy acids are used topically, while others are used orally, intravaginally, or by inhalation. See specific monographs for safety information.

PREGNANCY AND LACTATION:
See specific monographs for safety information.

(Read more about ALPHA HYDROXY ACIDS (AHAs))

LIKELY SAFE ...when the flower preparations are used orally or topically and appropriately (4,19779,36931,39503,93552,93557,96647,105088).

PREGNANCY: LIKELY UNSAFE
when used orally; contraindicated due to spermatocide, antiblastocyst, and abortifacient effects. There is insufficient reliable information available about the safety of calendula when used topically during pregnancy (4).

LACTATION:
Insufficient reliable information available; avoid using.

(Read more about CALENDULA)

LIKELY SAFE ...when undegraded carrageenan is used orally in the amounts found in foods (11). Carrageenan has Generally Recognized as Safe (GRAS) status in the US (4912,102538).

POSSIBLY SAFE ...when used intranasally, short-term. Saline solution containing iota-carrageenan 0.12% has been sprayed into the nose with apparent safety three times daily for up to 7 days (99449,99450,99451,99452,99466). Also, saline solution containing iota-carrageenan 0.17% has been sprayed into both nostrils with apparent safety four times daily (providing 1 mg daily) for up to 21 days (107852).

POSSIBLY UNSAFE ...when the degraded form, called poligeenan, is used orally. Poligeenan contains a lower molecular weight product that is partially absorbed. There is concern about the safety of this form because it has been linked to colonic lesions, neoplasms, and bleeding in animals (40065,40047). Due to public concern that commercial carrageenan contains poligeenan or can be degraded to poligeenan in the stomach, the United States Food and Drug Administration (FDA) reevaluated the safety of carrageenan and reaffirmed its status as GRAS in 2012 (99466). Carrageenan that is not degraded has an average molecular weight of 453-652 kDA, while degraded carrageenan is usually 20-30 kDA. In order to limit potential safety concerns, the European Commission Scientific Committee on Food advises that the total weight of any carrageenan food additives contain no more than 5% of a molecular weight below 50 kDa (99901). There is insufficient reliable information available about the safety of carrageenan when used topically.

PREGNANCY AND LACTATION: LIKELY SAFE
when used in food amounts (11). There is insufficient reliable information available about the safety of using larger amounts; avoid using.

(Read more about CARRAGEENAN)

LIKELY SAFE ...when used rectally and appropriately. Glycerol rectal suppositories and enemas are approved by the US Food and Drug Administration (FDA) for over-the-counter use to treat occasional constipation (15,272). ...when used topically and appropriately as a lotion, emulsion, or humectant (15,272,93754,93758,93759,99164).

POSSIBLY SAFE ...when used orally, short-term. Glycerol has been used with apparent safety in clinical trials at doses of up to 1.5 grams/kg (2474,2475,99162).

POSSIBLY UNSAFE ...when used intravenously. While some research suggests that intravenous glycerol can be safely administered for two consecutive days twice monthly for up to 6 months (106649), in another study, hemolysis was reported in 98% of patients treated with intravenous glycerol for acute ischemic stroke (2482).

CHILDREN: LIKELY SAFE
when used rectally and appropriately. Glycerol rectal suppositories and enemas are approved by the US FDA for over-the-counter use to treat occasional constipation in children 2 years of age and older (15,272). ...when used topically and appropriately as an emulsion or humectant in children 1 month of age and older (15,272,93756).

CHILDREN: POSSIBLY SAFE
when used orally, short-term. Glycerol has been used with apparent safety in clinical trials in children 2 months to 16 years of age at doses of 1.5 gram/kg, up to a maximum dose of 25 grams, taken every 6 hours (93762,93763).

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

(Read more about GLYCEROL)

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

POSSIBLY SAFE ...when used orally and appropriately for medicinal purposes. A grapefruit seed extract has been safely used in clinical research (5866). In addition, capsules containing grapefruit pectin 15 grams daily have been used in clinical research for up to 16 weeks (2216).

POSSIBLY UNSAFE ...when used orally in excessive amounts. Preliminary population research shows that consuming a quarter or more of a whole grapefruit daily is associated with a 25% to 30% increased risk of postmenopausal breast cancer (14858). Grapefruit juice is thought to reduce estrogen metabolism resulting in increased endogenous estrogen levels. More evidence is needed to validate this finding.

PREGNANCY AND LACTATION:
There is insufficient reliable information available about the safety of using medicinal amounts of grapefruit during pregnancy and lactation; avoid using.

(Read more about GRAPEFRUIT)

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

POSSIBLY SAFE ...when inhaled in amounts used for aromatherapy, short-term. Lemon essential oil has been used with apparent safety as aromatherapy for up to 2 weeks in clinical research (93475,98128,98129). There is insufficient reliable information available about the safety of lemon when used topically, or when used orally or intranasally in medicinal amounts.

PREGNANCY AND LACTATION:
Insufficient reliable information available. Avoid using in amounts greater than those typically found in foods.

(Read more about LEMON)

LIKELY SAFE ...when rose hip extract is used orally in the amounts found in foods. Rose hip extract has Generally Recognized as Safe (GRAS) status in the US (4912). ...when rose hip from Rosa canina is used orally and appropriately in medicinal amounts. A specific formulation of rose hip powder from Rosa canina (LitoZin/i-flex, Hyben Vital), taken in doses of up to 2.5 grams (5 capsules) twice daily, has been safely used for up to 6 months (17416,71641,71646,71658,71660,71661,104557). Rose hip powder from Rosa canina, 40 grams daily mixed in apple juice, has been used safely for up to 6 weeks (18104). Rose hip powder from Rosa canina, 500 mg twice daily for 20 days, has also been safely used (97938).

POSSIBLY SAFE ...when rose hip from Rosa damascena is used orally and appropriately in medicinal amounts. Rose hip extract from Rosa damascena has been used safely in doses of 200 mg every 6 hours for 3 days (104555). There is insufficient reliable information available about the safety of medicinal amounts of rose hip from other Rosa species. There is also insufficient reliable information available about the safety of rose hip when used topically.

PREGNANCY AND LACTATION:
There is insufficient reliable information available about the safety of rose hip when used orally or topically in medicinal amounts; avoid using in amounts greater than those found in foods.

(Read more about ROSE HIP)

LIKELY SAFE ...when used orally and appropriately in amounts commonly found in foods. When used as a substitute for other dietary oils, the recommended intake of high-oleic acid sunflower oil is 20 grams (1.5 tablespoons) daily (9780,98563). ...when used topically and appropriately, short-term. Sunflower oil has been applied to the skin twice daily for up to 6 weeks (76687). There is insufficient reliable information available about the safety of sunflower oil when used as an oral rinse.

CHILDREN: LIKELY SAFE
when used orally and appropriately in amounts commonly found in foods.

CHILDREN: POSSIBLY SAFE
when applied topically and appropriately, short-term. Sunflower oil has been applied to the skin of infants daily for up to 2 months (96144,96145,105524,108143). There is insufficient reliable information available about the safety of sunflower oil when used orally in larger amounts as medicine.

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately in amounts commonly found in foods. There is insufficient reliable information available about the safety of sunflower oil when used in amounts greater than those found in food.

(Read more about SUNFLOWER OIL)

(Read more about ALPHA HYDROXY ACIDS (AHAs))

CNS DEPRESSANTS Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, calendula might have additive effects when used with CNS depressants, although this appears to be unlikely.  Details Although some animal research has suggested that a saponoside constituent in calendula may have sedative effects (39545,39547), calendula has been used for over 30 years without reports of sedation in humans (105088).

(Read more about CALENDULA)

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, carrageenan may increase the risk of bleeding in patients taking anticoagulant or antiplatelet drugs.  Details Laboratory research suggests that carrageenan has anticoagulant effects (6002). However, this has not been reported in humans.

(Read more about CARRAGEENAN)

(Read more about GLYCEROL)

ACEBUTOLOL (Sectral) Interaction Rating = Minor Be watchful with this combination. Severity = Insignificant •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice can decrease blood levels of acebutolol, potentially decreasing the clinical effects of acebutolol.  Details Clinical research shows that grapefruit juice can modestly decrease acebutolol levels by 7% and reduce peak plasma concentration by 19% by inhibiting organic anion transporting polypeptide (OATP) (17603,18101). The acebutolol half-life is also extended by 1.1 hours when grapefruit juice is consumed concomitantly (18101). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction (17603,17604).

ALISKIREN (Tekturna, Rasilez) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice can decrease blood levels of aliskiren, potentially decreasing the clinical effects of aliskiren.  Details Clinical research shows that grapefruit juice can decrease aliskiren levels by approximately 60% by inhibiting organic anion transporting polypeptide (OATP) (91428). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction (17603,17604).

AMIODARONE (Cordarone) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of amiodarone, potentially increasing the effects and adverse effects of amiodarone.  Details Clinical research shows that grapefruit juice inhibits metabolism and increases absorption of amiodarone. Grapefruit juice increases amiodarone plasma levels by 50% and peak concentration by 84% (17601,17672,22120).

AMPRENAVIR (Agenerase) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice might decrease blood levels of amprenavir, although this is not likely to be clinically significant.  Details Some clinical research shows that grapefruit juice can slightly decrease amprenavir levels (17673); however, this is probably not clinically significant.

ARTEMETHER (Artenam, Paluther) Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of oral artemether, potentially increasing the effects and adverse effects of artemether.  Details Clinical research shows that grapefruit juice increases the levels of oral artemether by 90% to 250% in healthy males (5065,5066).

BENZODIAZEPINES Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice might increase blood levels of some oral benzodiazepines, potentially increasing the effects and adverse effects of these drugs.  Details Clinical research shows that grapefruit juice can increase plasma triazolam concentrations. Repeated consumption of grapefruit juice greatly increases triazolam concentrations and prolongs the half-life, probably due to inhibition of cytochrome P450 3A4 (CYP3A4) (7776,22118,22131,22133). Some studies show that grapefruit juice, particularly when taken in large quantities, reduces the clearance and increases the maximum blood levels, area under the plasma concentration curve (AUC), and duration of effect of midazolam. However, there is no effect on intravenous midazolam (4300,10159,11275,17601,22117,22119,16711,91427,95978). Grapefruit juice has also been shown to increase the maximum blood levels and duration of effect of diazepam, but the clinical significance of this is not known (3228). This interaction does not appear to occur with alprazolam (17674).

BLONANSERIN (Lonasen) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of blonanserin, potentially increasing the effects and adverse effects of blonanserin.  Details Blonanserin is metabolized primarily by cytochrome P450 3A4 (CYP3A4). A small clinical study shows that taking grapefruit juice along with oral blonanserin increases exposure to blonanserin almost 6-fold due to inhibition of intestinal CYP3A4 by grapefruit juice and prolongs the elimination half-life of blonanserin by 2.2-fold due to inhibition of hepatic CYP3A4 by grapefruit juice (96943).

BUDESONIDE (Entocort, UCERIS) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of budesonide, potentially increasing the effects and adverse effects of budesonide.  Details Budesonide is metabolized by cytochrome P450 3A4 (CYP3A4). A small clinical study shows that taking grapefruit juice along with oral budesonide increases the plasma concentration of budesonide. This effect is attributed to grapefruit-induced inhibition of CYP3A4 in both the colon and small intestine (91425).

BUSPIRONE (BuSpar) Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of buspirone, potentially increasing the effects and adverse effects of buspirone.  Details Clinical research shows that grapefruit juice increases absorption and plasma concentrations of buspirone (3771).

CAFFEINE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Grapefruit juice can decrease the clearance of caffeine, potentially increasing the effects and adverse effects of caffeine.  Details Clinical research shows that grapefruit juice decreases caffeine clearance (4300).

CALCIUM CHANNEL BLOCKERS Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of oral calcium channel blockers, potentially increasing the effects and adverse effects of these drugs.  Details Clinical research shows that grapefruit juice increases absorption and plasma concentrations of amlodipine (523), nifedipine (528,22114), nisoldipine (529), verapamil (7779,8285), felodipine, nimodipine, nicardipine, diltiazem, pranidipine, nitrendipine, and manidipine (524,528,1388,4300,7780,11276,22136,53338,22138,22139) (22140,22141,22142,22143,22147,22148,22149,53367,22158), This interaction is likely the result of the inhibition of intestinal metabolism of these drugs by CYP3A4 (7779,7780), although some research suggests grapefruit may alter plasma drug levels by reducing the rate of gastric emptying (22167). Consuming grapefruit juice 1 liter daily increases steady state concentrations of verapamil by as much as 50% (8285). However, some references dispute the clinical relevance of the interactions with amlodipine, diltiazem, and verapamil (3230,4300,22159). Other research in healthy individuals suggests plasma levels of felodipine and nifedipine are not affected when given intravenously (22144,22146). There is considerable interindividual variability in the effect of grapefruit juice on drug metabolism, which might account for inconsistent study results (7777,7779,8285). In healthy older adults, the hemodynamic response to felodipine plus grapefruit juice might be influenced by altered autonomic regulation. In older healthy adults, a single dose of grapefruit juice and felodipine enhanced the blood pressure-lowering effects of felodipine. However, after a week of grapefruit juice and felodipine (steady state), the hypotensive activity was reduced, possibly due to compensatory tachycardia (1392). Research indicates it is necessary to withhold grapefruit juice for as long as 3 days to avoid interactions with felodipine and nisoldipine (5068,5069,6453,22145).

CARBAMAZEPINE (Tegretol) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of carbamazepine, potentially increasing the effects and adverse effects of carbamazepine.  Details Clinical research shows that grapefruit juice increases absorption and plasma concentrations of carbamazepine (524).

CARVEDILOL (Coreg) Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of carvedilol, potentially increasing the effects and adverse effects of carvedilol.  Details Clinical research shows that grapefruit juice increases the bioavailability of a single dose of carvedilol by 16% (5071).

CELIPROLOL (Celicard) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can decrease blood levels of celiprolol, potentially decreasing the clinical effects of celiprolol.  Details In human research, taking grapefruit juice within two hours of celiprolol appears to decrease absorption and blood levels of celiprolol by approximately 85% (91421). This interaction is due to grapefruit-induced inhibition of organic anion transporting polypeptide (OATP) (17603,17604,22161). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction (17603,17604).

CISAPRIDE (Propulsid) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of cisapride, potentially increasing the effects and adverse effects of cisapride.  Details Clinical research shows that grapefruit juice increases the absorption and plasma concentrations of cisapride. According to the cisapride prescribing information, grapefruit juice is contraindicated in patients taking cisapride (1383,3226,17601,22164,22165).

CLOMIPRAMINE (Anafranil) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = D Theoretically, grapefruit juice might increase blood levels of clomipramine, potentially increasing the effects and adverse effects of clomipramine.  Details Case reports have shown that clomipramine trough levels increase significantly after the addition of grapefruit juice to the therapeutic regimen (5064).

CLOPIDOGREL (Plavix) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can decrease blood levels of the active metabolite of clopidogrel, thereby decreasing the antiplatelet effect of clopidogrel.  Details Clopidogrel is an antiplatelet prodrug that is metabolized primarily by cytochrome P450 2C19 (CYP2C19) to form the active metabolite. A small clinical study shows that taking grapefruit juice with clopidogrel decreases plasma levels of the active metabolite by more than 80% and impairs the antiplatelet effect of clopidogrel. This effect is possibly due to grapefruit-induced inhibition of CYP2C19 (91419).

COLCHICINE Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Theoretically, grapefruit juice might increase blood levels of colchicine, potentially increasing the effects and adverse effects of colchicine.  Details Colchicine is an alkaloid that undergoes P-glycoprotein (P-gp) mediated drug efflux in the intestines, followed by metabolism by cytochrome P450 3A4 (CYP3A4). There is concern that grapefruit juice will increase the effects and adverse effects of colchicine due to grapefruit-induced inhibition of P-gp and/or CYP3A4. In vitro evidence shows that grapefruit juice increases absorption of colchicine by inhibiting P-gp (94158). A case of acute colchicine toxicity has been reported for an 8-year-old female who drank grapefruit juice while taking high-dose colchicine, long-term (94157). However, one small clinical study in healthy adults shows that drinking grapefruit juice 240 mL twice daily for 4 days does not affect the bioavailability or adverse effects of a single dose of colchicine 0.6 mg taken on the fourth day (35762).

CYCLOSPORINE (Neoral, Sandimmune) Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of oral cyclosporine, potentially increasing the effects and adverse effects of cyclosporine.  Details Clinical research shows that grapefruit juice increases the absorption and plasma concentrations of cyclosporine (522,11270,22113,22150,22152,22153,22154,22155). The mechanism of action is unclear. However, there is no effect on intravenous cyclosporine (22151).

CYTOCHROME P450 1A2 (CYP1A2) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, grapefruit juice might increase levels of drugs metabolized by CYP1A2.  Details In vitro research suggests that grapefruit juice might inhibit CYP1A2 enzymes (12479). So far, this interaction has not been reported in humans.

CYTOCHROME P450 2C19 (CYP2C19) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, grapefruit juice might increase levels of drugs metabolized by CYP2C19.  Details In vitro research suggests that grapefruit juice might inhibit CYP2C19 enzymes (12479). Also, a small clinical study shows that taking grapefruit juice with clopidogrel, an antiplatelet prodrug that is metabolized primarily by CYP2C19, decreases plasma levels of the active metabolite and impairs the antiplatelet effect of clopidogrel. This effect is likely due to grapefruit-induced inhibition of CYP2C19 (91419).

CYTOCHROME P450 2C9 (CYP2C9) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, grapefruit juice might increase levels of drugs metabolized by CYP2C9.  Details In vitro research suggests that grapefruit juice might inhibit CYP2C9 enzymes (12479). So far, this interaction has not been reported in humans.

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase levels of drugs metabolized by CYP3A4.  Details Clinical research shows that grapefruit juice can inhibit CYP3A4 metabolism of drugs, causing increased drug levels and potentially increasing the risk of adverse effects (3227,3774,8283,8285,8286,22129,91427,104190). When taken orally, effects of grapefruit juice on CYP3A4 levels appear to last at least 48 hours (91427). Grapefruit's ability to inhibit CYP3A4 has even been harnessed to intentionally increase levels of venetoclax, which is metabolized by CYP3A4, in an elderly patient with acute myeloid leukemia who could not afford full dose venetoclax. The lower dose of venetoclax in combination with grapefruit juice resulted in serum levels of venetoclax in the therapeutic reference range of full dose venetoclax and positive treatment outcomes for the patient (112287). Professional consensus recommends the consideration of patient age, existing medical conditions, additional medications, and the potential for additive adverse effects when evaluating the risks of concomitant use of grapefruit juice with any medication metabolized by CYP3A4. While all patients are at risk for interactions with grapefruit juice consumption, patients older than 70 years of age and those taking multiple medications are at the greatest risk for a serious or fatal interaction with grapefruit juice (95970,95972).

DAPOXETINE (Priligy) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of dapoxetine, potentially increasing the effects and adverse effects of dapoxetine.  Details Pharmacokinetic research shows that drinking grapefruit juice 250 mL prior to taking dapoxetine 60 mg can increase the maximum plasma concentration of dapoxetine by 80% and prolong the elimination half-life by 43%. This effect is attributed to the inhibition of both intestinal and hepatic cytochrome P450 3A4 (CYP3A4) by grapefruit (95975).

DEXTROMETHORPHAN (Robitussin DM, others) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of dextromethorphan, potentially increasing the effects and adverse effects of dextromethorphan.  Details Clinical research shows that grapefruit juice can inhibit cytochrome P450 3A4 (CYP3A4) metabolism, causing increased dextromethorphan levels (11362).

ERYTHROMYCIN Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of erythromycin, potentially increasing the effects and adverse effects of erythromycin.  Details Clinical research shows that concomitant use of erythromycin with grapefruit can inhibit cytochrome P450 3A4 (CYP3A4) metabolism of erythromycin, increasing plasma concentrations of erythromycin by 35% (8286).

ESTROGENS Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of estrogens, potentially increasing the effects and adverse effects of estrogens.  Details Clinical research shows that grapefruit increases the levels of endogenous and exogenous estrogens by inhibiting cytochrome P450 3A4 (CYP3A4) enzymes (525,526,14858). Grapefruit juice increases exogenously administered 17-beta-estradiol by about 20% in females without ovaries and ethinyl-estradiol in healthy females (525,526,22160).

ETOPOSIDE (VePesid) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can decrease blood levels of etoposide, potentially decreasing the clinical effects of etoposide.  Details Clinical research shows that grapefruit juice decreases the absorption and plasma concentrations of etoposide. There is some evidence that grapefruit juice co-administered with oral etoposide can reduce levels of etoposide by about 26% (8744). Grapefruit juice seems to inhibit organic anion transporting polypeptide (OATP), which is a drug transporter in the gut, liver, and kidney (7046,17603,17604). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction (17603,17604).

FEXOFENADINE (Allegra) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can decrease blood levels of fexofenadine, thereby decreasing the clinical effects of fexofenadine.  Details Clinical research shows that grapefruit juice can significantly decrease oral absorption and blood levels of fexofenadine. In one study, consuming a drink containing grapefruit juice 25% decreased bioavailability of fexofenadine by about 24%. Consuming a full-strength grapefruit juice drink reduced bioavailability by 67% (7046). In another study, consuming grapefruit juice 300 mL decreased fexofenadine levels by 42%. Consuming 1200 mL of grapefruit juice reduced levels by 64% (17602). Similarly, drinking grapefruit juice 240 mL decreased the oral bioavailability of fexofenadine by 25% in another pharmacokinetic study (112288). Fexofenadine manufacturer data indicates that concomitant administration of grapefruit juice and fexofenadine results in larger wheal and flare sizes in research models. This suggests that grapefruit also reduces the clinical response to fexofenadine (17603). Grapefruit juice seems to inhibit organic anion transporting polypeptide (OATP), which is a drug transporter in the gut, liver, and kidney (7046,17603,17604,22161). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction (17603,17604).

FLUVOXAMINE (Luvox) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice can increase blood levels of fluvoxamine, potentially increasing the effects and adverse effects of fluvoxamine.  Details Clinical research shows that grapefruit juice inhibits metabolism and increases fluvoxamine levels and peak concentration (17675).

HALOFANTRINE Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of halofantrine, potentially increasing the effects and adverse effects of halofantrine.  Details Clinical research shows that grapefruit juice inhibits cytochrome P450 3A4 (CYP3A4) metabolism, which increases halofantrine levels and peak concentration, as well as a marker of ventricular tachyarrhythmia potential (22129).

HMG-CoA REDUCTASE INHIBITORS ("Statins") Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of statins that are metabolized by cytochrome P450 3A4 (CYP3A4), potentially increasing the effects and adverse effects of these statins. Additionally, grapefruit juice might interfere with the bioavailability of statins that are substrates of organic anion transporting polypeptides (OATP).  Details Clinical research shows that grapefruit juice inhibits metabolism and increases absorption and plasma concentrations of statins that are metabolized by CYP3A4. These include lovastatin (527,11274), simvastatin (3774,7782,22127), and atorvastatin (3227,12179,22126). Keep in mind that there is considerable variability in the effect of grapefruit juice on drug metabolism, so individual patient response is difficult to predict (7777,7781). Some statins, including pravastatin, fluvastatin, pitavastatin, and rosuvastatin, are not metabolized by CYP3A4. However, grapefruit juice might still affect the bioavailability of these statins. These statins are substrates of OATP. Grapefruit juice can inhibit OATP. Therefore, grapefruit juice may reduce the bioavailability or increase drug levels of these statins depending on the type of OATP. However, grapefruit juice affects OATP for only a short time. Therefore, separating drug administration by at least 4 hours is likely to avoid this interaction (3227,12179,17601,22126,91420).

ITRACONAZOLE (Sporanox) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice can interfere with itraconazole absorption, although the clinical significance of this interaction is unclear.  Details Clinical research shows that grapefruit juice can affect itraconazole absorption and might increase or decrease itraconazole levels (310,17601,22123).

LEVOTHYROXINE (Synthroid, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice can decrease blood levels of levothyroxine, potentially decreasing the effectiveness of levothyroxine.  Details Clinical research shows that grapefruit juice modestly decreases levothyroxine levels by 11% by inhibiting organic anion transporting polypeptide (OATP) (17604,22163). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction (17603,17604).

LOSARTAN (Cozaar) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can decrease blood levels of the active metabolite of losartan, potentially decreasing the clinical effects of losartan.  Details Losartan is an inactive prodrug which must be metabolized to its active form, E-3174, to be effective. In one human study, grapefruit juice reduced losartan metabolism, increased losartan AUC, and reduced the AUC of the major active losartan metabolite, E-3174 (1391).

METHADONE (Dolophine) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of methadone, potentially increasing the effects and adverse effects of methadone.  Details Clinical research shows that grapefruit juice inhibits the metabolism of methadone, increasing methadone levels and peak concentrations (17676). In one case, a 51-year-old male taking methadone 90 mg daily and no other medications was found unresponsive. The patient reported drinking grapefruit juice 500 mL daily for 3 days prior to the event. Methadone is a substrate of cytochrome P450 3A4 (CYP3A4), and grapefruit juice-induced inhibition of CYP3A4 is the likely cause of this interaction (102056).

METHYLPREDNISOLONE Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of methylprednisolone, potentially increasing the effects and adverse effects of methylprednisolone.  Details Clinical research shows that grapefruit juice can increase the plasma concentration of orally administered methylprednisolone. Grapefruit juice 200 mL three times daily given with methylprednisolone 16 mg increased methylprednisolone half-life by 35%, peak plasma concentration by 27%, and total area under the curve by 75% (3123).

NADOLOL (Corgard) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice might decrease blood levels of nadolol, potentially decreasing the clinical effects of nadolol.  Details Nadolol is a substrate of organic anion transporting polypeptide 1A2 (OATP1A2) (17603,17604,22161). Some research shows that grapefruit juice and its constituent naringin can inhibit organic anion transporting polypeptides (OATP), which can reduce the bioavailability of OATP substrates (17603,17604,22161,91427). However, preliminary clinical research shows that grapefruit juice containing a low amount of naringin does not significantly affect levels of nadolol (91422). It is not known if grapefruit juice containing higher amounts of naringin reduces the bioavailability of nadolol.

NILOTINIB (Tasigna) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of nilotinib, potentially increasing the effects and adverse effects of nilotinib.  Details Clinical research shows that grapefruit juice inhibits metabolism and increases absorption of nilotinib. Grapefruit juice increases nilotinib levels by 29% and peak concentration by 60% (17677).

ORGANIC ANION-TRANSPORTING POLYPEPTIDE SUBSTRATES (OATP) Interaction Rating = Major Do not take this combination. Severity = Moderate •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can decrease levels of drugs that are substrates of OATP.  Details In vitro and clinical research show that consuming grapefruit juice inhibits OATP, which reduces the bioavailability of oral drugs that are substrates of OATP. Various clinical studies have shown reduced absorption of OATP substrates when taken with grapefruit, including fexofenadine, acebutolol, aliskiren, celiprolol, levothyroxine, nadolol, and pitavastatin (17603,17604,18101,22126,22134,22161,22163,91420,91427,91428,112288). Grapefruit juice is thought to affect OATP for only a short time. Therefore, separating drug administration and consumption of grapefruit by at least 4 hours is likely to prevent this interaction (17603,17604).

OXYCODONE (Oxycontin) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of oxycodone, potentially increasing the effects and adverse effects of oxycodone.  Details Oxycodone is metabolized by both cytochrome P450 3A4 (CYP3A4) and cytochrome P450 2D6 (CYP2D6). A small clinical study shows that grapefruit juice can increase plasma levels of oral oxycodone about 1.7-fold by inhibiting CYP3A4. While the analgesic effects of oxycodone do not seem to be affected, taking grapefruit juice along with oxycodone may theoretically increase the adverse effects of oxycodone (91423).

P-GLYCOPROTEIN SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice does not seem to affect renal P-glycoprotein (P-gp). Theoretically, it might inhibit intestinal P-gp, but evidence is conflicting.  Details While most in vitro research shows that grapefruit products inhibit P-gp, (1390,11270,11278,11362,95976), research in humans is less clear. Two small clinical studies in healthy adults using digoxin as a probe substrate show that grapefruit juice does not inhibit P-gp in the kidneys (11277,11282). It is unclear whether this applies to intestinal P-gp, for which digoxin is not considered to be a sensitive probe (105568). Grapefruit juice has been shown to reduce levels of fexofenadine (7046,17602,112288), and increase levels of quinidine (5067,22121). However, as both of these drugs are also substrates of other enzymes and transporters, it is unclear what role, if any, intestinal P-gp has in these findings.

PITAVASTATIN (Livalo) Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of pitavastatin, potentially increasing the effects and adverse effects of pitavastatin.  Details Pharmacokinetic research shows that taking grapefruit juice with pitavastatin 2-4 mg can increase blood levels of pitavastatin by 13% to 14%. Unlike simvastatin and atorvastatin, pitavastatin is not significantly metabolized by cytochrome P450 3A4 (CYP3A4) enzymes. Grapefruit juice appears to increase levels of pitavastatin by inhibiting its uptake by organic anion transporting polypeptide 1B1 (OATP1B1) into hepatocytes for metabolism and clearance from the body (22126,91420). Grapefruit juice seems to increase levels of pitavastatin to a greater degree in patients homozygous for a specific polymorphism (388A>G) in the OATP1B1 gene compared to those heterozygous for this polymorphism (91420).

PRASUGREL (Effient) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can decrease blood levels of the active metabolite of prasugrel, thereby decreasing the antiplatelet effect of prasugrel.  Details Prasugrel is a prodrug that is metabolized by cytochrome P450 3A4 (CYP3A4) into its active metabolite. A small pharmacokinetic study in healthy volunteers shows that drinking grapefruit juice 200 mL three times daily for 4 days and taking a single dose of prasugrel 10 mg with an additional 200 mL of grapefruit juice on day 3, results in a 49% lower peak plasma level and a 26% lower overall plasma exposure to the active metabolite when compared with drinking water. However, despite the reduced exposure, platelet aggregation seems to be reduced by an average of only 5% (105567). The clinical significance of this interaction is unclear.

PRAZIQUANTEL (Biltricide) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of praziquantel, potentially increasing the effects and adverse effects of praziquantel.  Details Clinical research shows that grapefruit juice can inhibit cytochrome P450 3A4 (CYP3A4) metabolism of praziquantel. Plasma concentrations of praziquantel can increase by as much as 160% when administered with 250 mL of commercially available grapefruit juice (8282).

PRIMAQUINE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice may increase blood levels of primaquine, potentially increasing the effects and adverse effects of primaquine.  Details Clinical research shows that grapefruit juice increases the bioavailability of primaquine by approximately 20% (22130). The clinical significance of this interaction is not clear.

QT INTERVAL-PROLONGING DRUGS Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit or grapefruit juice, especially if consumed in large amounts, can cause additive QT interval prolongation when taken with QT interval-prolonging drugs, potentially increasing the risk of ventricular arrhythmias.  Details Clinical research in healthy volunteers shows that drinking 6 liters of grapefruit juice over 6 hours prolonged the QTc by a peak amount of 14 milliseconds (ms). This prolongation was similar to the QT prolongation caused by the drug moxifloxacin. In individuals with long QT syndrome, a smaller dose of grapefruit juice, 1.5 liters, resulted in a greater peak QTc prolongation of about 30 ms (100249). The effect of smaller quantities of grapefruit juice on the QT interval is unclear.

QUETIAPINE (Seroquel) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice may increase blood levels of quetiapine, increasing the effects and adverse effects of quetiapine.  Details Quetiapine is metabolized by cytochrome P450 3A4 (CYP3A4). Grapefruit can inhibit CYP3A4 (3227,3774,8283,8285,8286,22129,91427,104190). In one case report, a healthy 28-year-old female with bipolar disorder stabilized on quetiapine 800 mg daily presented with quetiapine toxicity considered to be related to consuming a gallon of grapefruit juice over the past 24 hours (108848).

QUINIDINE Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can alter blood levels of quinidine, potentially increasing or decreasing the clinical effects of quinidine.  Details Clinical research shows that grapefruit juice decreases quinidine absorption, clearance, and metabolism, and prolongs the half-life by about 20% (5067,22121).

SAQUINAVIR (Fortovase, Invirase) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of saquinavir, potentially increasing the effects and adverse effects of saquinavir.  Details Clinical research shows that grapefruit juice increases the absorption and plasma concentrations of saquinavir (3773,22132).

SCOPOLAMINE (Transderm Scop) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of scopolamine, potentially increasing the effects and adverse effects of scopolamine.  Details Clinical research shows that grapefruit juice can inhibit cytochrome P450 3A4 (CYP3A4) metabolism of scopolamine, increasing its absorption and plasma concentrations. Oral bioavailability of scopolamine can increase by 30% when administered with 150 mL of grapefruit juice (8284).

SERTRALINE (Zoloft) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice can increase blood levels of sertraline, potentially increasing the effects and adverse effects of sertraline.  Details Clinical research shows that grapefruit juice inhibits the cytochrome P450 3A4 (CYP3A4) metabolism of sertraline, increasing blood levels of sertraline (22122).

SILDENAFIL (Viagra) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of sildenafil, potentially increasing the effects and adverse effects of sildenafil.  Details Clinical research shows that grapefruit juice inhibits cytochrome P450 3A4 (CYP3A4) metabolism of sildenafil, increasing its absorption and plasma concentrations. Oral bioavailability of sildenafil can increase by 23% when administered with 500 mL of commercially available grapefruit juice (8283).

SUNITINIB (Sutent) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Unlikely •  Level of Evidence = B Grapefruit juice may slightly increase blood levels of sunitinib, potentially increasing the effects and adverse effects of sunitinib.  Details Sunitinib is metabolized by cytochrome P450 3A4 (CYP3A4). Grapefruit and grapefruit juice can inhibit CYP3A4 and increase levels of some drugs metabolized by this enzyme. One small clinical study shows that drinking 200 mL of grapefruit juice three times daily can increase the bioavailability of sunitinib by 11% (91429). While this effect is unlikely to be clinically significant, patients should use caution when using grapefruit along with sunitinib. Dose adjustments may be necessary.

TACROLIMUS (Prograf) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Likely •  Level of Evidence = B Grapefruit juice can increase blood levels of tacrolimus, potentially increasing the effects and adverse effects of tacrolimus.  Details Clinical research shows that drinking grapefruit juice 200 mL daily while taking tacrolimus 3 mg daily increases the trough blood concentration of tacrolimus by approximately 3-fold in patients with connective tissue diseases (95974). A single case has also reported a 10-fold increase in tacrolimus trough levels after the ingestion of grapefruit juice over 3 days (22122). This effect is attributed to the inhibition of cytochrome P450 3A4 (CYP3A4) by grapefruit (95974).

TADALAFIL (Cialis) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, grapefruit juice might increase blood levels of tadalafil, potentially increasing the effects and adverse effects of tadalafil.  Details Animal research shows that grapefruit juice increases tadalafil serum concentrations and overall exposure, likely through inhibition of cytochrome P450 3A4 enzymes (104189).

TALINOLOL Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Grapefruit juice might decrease blood levels of talinolol, potentially decreasing the clinical effects of talinolol.  Details Clinical research suggests that grapefruit juice reduces talinolol bioavailability, likely by inhibiting intestinal uptake (22135). The clinical significance of this effect is unclear.

TERFENADINE (Seldane) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of terfenadine, potentially increasing the effects and adverse effects of terfenadine.  Details Clinical research shows that grapefruit juice increases the absorption and plasma concentrations of terfenadine (530,22124,22125). The mechanism of action is unclear.

THEOPHYLLINE Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can decrease blood levels of theophylline, potentially decreasing the effectiveness of theophylline.  Details Clinical research shows that grapefruit juice seems to modestly decrease theophylline levels when given concurrently with sustained-release theophylline (11013). The mechanism of this interaction is unknown.

TICAGRELOR (Brilinta) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of ticagrelor, thereby increasing the effects and adverse effects of ticagrelor.  Details Ticagrelor is metabolized by cytochrome P450 3A4 (CYP3A4). Grapefruit can inhibit CYP3A4. A small clinical study shows that taking grapefruit juice with ticagrelor increases blood levels of ticagrelor more than two-fold and increases the antiplatelet activity of ticagrelor (91418).

TOLVAPTAN (Samsca) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Grapefruit juice can increase blood levels of tolvaptan, potentially increasing the effects and adverse effects of tolvaptan.  Details Tolvaptan is metabolized by cytochrome P450 3A4 (CYP3A4). Grapefruit can inhibit CYP3A4. A small clinical study shows that grapefruit juice can increase the bioavailability and blood levels of tolvaptan by approximately 1.6-fold for up to 16 hours (91426).

WARFARIN (Coumadin) Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, drinking large amounts of grapefruit juice might increase the effects and adverse effects of warfarin.  Details In one case report, a patient experienced significantly increased international normalized ratio (INR) associated with consumption of 50 ounces of grapefruit juice daily (12061). However, smaller amounts of grapefruit juice might not be a problem. In a small clinical trial, consumption of 24 ounces of grapefruit juice daily for one week had no effect on INR in males treated with warfarin (12063).

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ITRACONAZOLE (Sporanox) Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, taking itraconazole capsules or tablets with a beverage containing lemon might increase the levels and clinical effects of itraconazole.  Details In one case report, dissolving itraconazole tablets in a small amount of specific beverages containing lemon prior to administration increased the level of itraconazole in a lung transplant patient. In this case, the increased bioavailability was desirable and was likely due to improved tablet dissolution in the acidic beverage (110781).

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ALKYLATING AGENTS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, the antioxidant effects of rose hip might reduce the effectiveness of alkylating agents but might also reduce the oxidative damage caused by certain alkylating agents.  Details Rose hip contains vitamin C. The use of antioxidants like vitamin C during chemotherapy is controversial. There is concern that antioxidants could reduce the activity of chemotherapy drugs that generate free radicals, such as cyclophosphamide, chlorambucil, carmustine, busulfan, and thiotepa (391). In contrast, some researchers theorize that antioxidants might make chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells (14012,14013). Further, some animal research suggests that the antioxidant effects of rose hip might attenuate cyclophosphamide-induced testicular toxicity (111413). More evidence is needed to determine what effect, if any, antioxidants found in rose hip, such as vitamin C, have on the effectiveness and adverse effects of chemotherapy.

ALUMINUM Interaction Rating = Moderate Be cautious with this combination. Severity = Mild •  Occurrence = Probable •  Level of Evidence = D Theoretically, rose hip might increase the amount of aluminum absorbed from aluminum compounds.  Details Rose hip contains vitamin C. Theoretically, vitamin C increases the absorption of aluminum. Concomitant use might increase aluminum absorption, but the clinical significance of this is unknown (3046). Administer rose hip two hours before or four hours after antacids.

ANTICOAGULANT/ANTIPLATELET DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, rose hip might reduce the effectiveness of anticoagulant or antiplatelet drugs.  Details In vitro and animal research suggests that a constituent of rose hip, rugosin E, can induce platelet aggregation (71653). This has not been shown in humans. Theoretically, concomitant use of rose hip might reduce the effectiveness of antiplatelet or anticoagulant drugs.

ANTITUMOR ANTIBIOTICS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, the antioxidant effects of rose hip might reduce the effectiveness of antitumor antibiotics.  Details Rose hip contains the antioxidant vitamin C. There is concern that antioxidants might reduce the activity of chemotherapy drugs that generate free radicals, such as antitumor antibiotics (391). In contrast, other researchers theorize that antioxidants might make antitumor antibiotic chemotherapy more effective by reducing oxidative stress that could interfere with apoptosis (cell death) of cancer cells (14012,14013). More evidence is needed to determine what effects, if any, antioxidants such as vitamin C have on antitumor antibiotic chemotherapy.

ASPIRIN Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Unlikely •  Level of Evidence = B Theoretically, rose hip might reduce the clearance of aspirin; however, its vitamin C content is likely too low to produce clinically significant effects.  Details Rose hip contains vitamin C. It has been suggested that acidification of the urine by vitamin C can decrease the urinary excretion of salicylates, increasing plasma salicylate levels (3046). However, short-term use of up to 6 grams daily of vitamin C does not seem to affect urinary pH or salicylate excretion (10588,10589). The vitamin C content of rose hip is typically about 500 mg per 100 grams. Thus, a clinically significant interaction between rose hip and aspirin is unlikely.

ESTROGENS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, rose hip might increase blood levels of estrogens.  Details Rose hip contains vitamin C. Increases in plasma estrogen levels of up to 55% have occured under some circumstances when vitamin C is taken concurrently with oral contraceptives or hormone replacement therapy, including topical products (129,130,11161). It is suggested that vitamin C prevents oxidation of estrogen in the tissues, regenerates oxidized estrogen, and reduces sulfate conjugation of estrogen in the gut wall (129,11161). When tissue levels of vitamin C are high, these processes are already maximized and supplemental vitamin C does not have any effect on estrogen levels. However, increases in plasma estrogen levels may occur when women who are deficient in vitamin C take supplements (11161).

LITHIUM Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = D Theoretically, rose hip might increase blood levels of lithium.  Details Rose hip is thought to have diuretic properties (5,18). Theoretically, due to these potential diuretic effects, rose hip might reduce excretion and increase levels of lithium. The dose of lithium might need to be decreased.

WARFARIN (Coumadin) Interaction Rating = Minor Be watchful with this combination. Severity = Moderate •  Occurrence = Unlikely •  Level of Evidence = D Theoretically, rose hip might reduce the effectiveness of warfarin; however, its vitamin C content is likely too low to produce clinically significant effects.  Details Rose hip contains vitamin C. High doses of vitamin C may reduce the response to warfarin, possibly by causing diarrhea and reducing warfarin absorption (11566). This occurred in two people who took up to 16 grams daily of vitamin C, and resulted in decreased prothrombin time (9804,9806). Lower doses of 5-10 grams daily of vitamin C can also reduce warfarin absorption, but this does not seem to be clinically significant (9805,9806,11566,11567). The vitamin C content of rose hip is typically about 500 mg per 100 grams. Thus, a clinically significant interaction between rose hip and warfarin is unlikely.

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ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, sunflower oil might decrease the effectiveness of antidiabetes medications.  Details A diet using sunflower oil as a fat source can cause increased fasting blood glucose levels in patients with type 2 diabetes (8132). Dose adjustments to diabetes medications might be necessary.

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General ...Alpha hydroxy acids represent a group of natural chemicals, some of which can cause adverse effects. See specific monographs for safety information.

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General ...Orally and topically, calendula is generally well tolerated.
Serious Adverse Effects (Rare):
All ROAs: Allergic reactions.

Dermatologic ...Topically, a preparation containing calendula powder 0. 1% resulted in inflammation around the wound to which it was applied (96647). Burning sensation, itching, redness, and scaling were reported rarely in patients applying a combination of calendula, licorice, and snail secretion filtrate to the face. The specific role of calendula is unclear (110322).

Immunologic ...Orally, calendula can cause allergic reactions. Topically, calendula can cause eczematous allergic reactions. Calendula-specific patch testing is recommended prior to usage to determine allergenic potential. Testing is particularly necessary in individuals sensitive to the Asteraceae/Compositae family (10691,11458,96647). Members of this family include ragweed, chrysanthemums, marigolds, daisies, and many other herbs. A preparation containing calendula powder 0.1% resulted in hives in a patient with a ragweed allergy (96647). Despite the widespread use of calendula and the occurrence of allergies to other family members, there has been only one report of anaphylaxis (11152).

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General ...Orally, carrageenan is well tolerated in amounts found in foods. Intranasally, carrageenan seems to be well tolerated.
Most Common Adverse Effects: None known.

Dermatologic ...Topically, when carrageenan gel was applied to the penis or anus prior to anal intercourse in one clinical study, it was reported to cause discomfort or adverse reactions in 59% of males, compared with 44% of those using placebo (107851).

Genitourinary ...Intravaginally, carrageenan gel has been associated with mild vaginal itching and burning, a vaginal abrasion, bladder fullness, and urinary hesitancy. However, it is unclear if carrageenan was the causal factor of these symptoms (40044,40068).

Hematologic ...In one clinical study in males, carrageenan gel applied topically to the penis and anus prior to anal intercourse was reported to cause rectal bleeding that was not directly related to anal intercourse in 8% of patients, compared with 0% of patients using placebo (107851).

Oncologic ...Observational research has found that increased consumption of carrageenan is associated with an increase in breast cancer incidence (40046).

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General ...Orally, rectally, and topically, glycerol seems to be well tolerated. Intravenously, glycerol may be unsafe.
Most Common Adverse Effects:
Orally: Bloating, diarrhea, nausea, vomiting, dizziness, and headache.
Topically: Burning, irritation, and pruritus.
Intravenously: Hemolysis in patients with acute ischemic stroke.

Dermatologic ...Topically, glycerol has been reported to cause burning, irritation, and pruritus (93754,93756). Rectally, the regular administration of glycerol 50% enemas has been reported to cause generalized urticaria in at least two patients; in both patients, symptoms resolved after discontinuation (110019,110025).

Gastrointestinal ...Orally, glycerol can cause bloating, nausea, vomiting, thirst, and diarrhea (15,2475).

Hematologic ...Intravenously, glycerol has been reported to caused hemolysis in people treated for acute ischemic stroke (2480,2482).

Neurologic/CNS ...Orally, glycerol can cause mild headache and dizziness (15,2475).

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General ...Orally, grapefruit and grapefruit juice are generally well tolerated.
Serious Adverse Effects (Rare):
Orally: Allergic reactions in sensitive individuals have been reported. When large quantities are consumed, arrhythmias, mineralocorticoid excess, QT prolongation, and pseudohyperaldosteronism have been reported. There is also some concern for increased breast cancer risk with grapefruit consumption.

Cardiovascular ...Orally, consumption of pink grapefruit juice 1000 mL can cause QT prolongation and cause arrhythmias in healthy patients and worsen arrhythmias in cardiomyopathy patients (13031,91424).

Endocrine ...Orally, high doses of grapefruit juice have been observed to cause pseudohyperaldosteronism and mineralocorticoid excess (53340,53346).

Gastrointestinal ...In a case report, grapefruit juice held against the teeth resulted in enamel and tooth surface loss (53368).

Immunologic ...Orally, grapefruit can cause allergic sensitization characterized by eosinophilic gastroenteritis, urticaria, and generalized pruritus (53351,53360).

Oncologic ...Preliminary population research shows that postmenopausal adults who consume a quarter or more of a whole grapefruit daily have a 25% to 30% increased risk of developing breast cancer (14858). Grapefruit is a potent inhibitor of cytochrome P450 3A4, which metabolizes estrogen. Consuming large amounts of grapefruit might significantly increase endogenous estrogen levels and therefore increase the risk of breast cancer. More evidence is needed to validate these findings. Until more is known, advise patients to consume grapefruit in moderation.

Renal ...In population research, consumption of 240 mL/day of grapefruit juice is associated with an increased risk of kidney stones (4216,53372).

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General ...Orally, lemon is well tolerated in amounts commonly found in foods. A thorough evaluation of safety outcomes has not been conducted on the use of larger amounts.
Most Common Adverse Effects:
Orally: Epigastralgia and heartburn with the regular consumption of fresh lemon juice.

Dermatologic ...Topically, the application of lemon oil might cause photosensitivity, due to furocoumarin derivative content. This occurs most often in fair-skinned people (11019).

Gastrointestinal ...Orally, fresh lemon juice, taken as 60 mL twice daily, has been reported to cause gastrointestinal disturbances in 37% of patients in one clinical trial, compared with 8% of patients in the placebo group. Specifically, of the patients consuming lemon juice, 21% experienced heartburn and 8% experienced epigastralgia, compared to 1% and 3%, respectively, in the placebo group (107489).

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General ...Orally, rose hip from Rosa canina is well tolerated. Rose hip from Rosa damascena also seems to be well tolerated. A thorough evaluation of safety outcomes has not been conducted for rose hip derived from other species.
Most Common Adverse Effects:
Orally: Flatulence, loose stools.

Dermatologic ...Orally, one case of mild urticaria has been reported in a clinical trial for a patient taking a specific rose hip powder product (LitoZin/i-flex, Hyben Vital) 2. 5 grams twice daily (71646).

Gastrointestinal ...Orally, gastrointestinal reactions have been reported. These include abdominal cramps, acid reflux, constipation, diarrhea, flatulence, nausea, vomiting, gastrointestinal obstruction, esophagitis, heartburn, acid reflux, and water brash. However, in most cases, these adverse effects occurred at the same frequency in patients taking placebo (15,18104,71641,71646,97938).
Rose hip powder is a source of vitamin C. Osmotic diarrhea and gastrointestinal upset have been reported with doses of vitamin C greater than the tolerable upper intake level (UL) of 2000 mg daily (4844). However, most rose hip products contain only 500 mg of vitamin C per 100 grams.

Genitourinary ...Orally, a few mild cases of frequent voiding have been reported in clinical trials. However, the frequency of occurrence does not seem to differ from those taking placebo (71641,71646).

Immunologic ...When inhaled in the workplace, rose hip dust has caused mild to moderate anaphylaxis (6).

Neurologic/CNS ...Orally, vertigo and headache have been reported rarely (97938).

Ocular/Otic ...A case of keratoconjunctivitis secondary to contact with rose hip has been reported. The adverse effect was attributed to irritant hairs found on the fruit of rose hip. Symptoms resolved after treatment with topical prednisolone 1% eye drops (71642).

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General ...Orally and topically, sunflower oil is well tolerated.
Serious Adverse Effects (Rare):
Orally: Allergic reactions in sensitive individuals have been reported.

Immunologic ...Orally, sunflower oil can cause an allergic reaction in individuals sensitive to the Asteraceae/Compositae family. Members of this family include ragweed, chrysanthemums, marigolds, daisies, and many other herbs. However, the protein content of sunflower oil is very low. In one case report, an allergic response to sunflower oil did not occur despite presenting with severe allergy and anaphylaxis to sunflower seed (108140).

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