Amara Pascoe by Pascoe Canada

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Allergic rhinitis (hay fever). Although there has been interest in using oral bitter orange for allergic rhinitis, there is insufficient reliable information about the clinical effects of bitter orange for this purpose.
• Androgenic alopecia. Although there has been interest in using topical bitter orange for androgenic alopecia, there is insufficient reliable information about the clinical effects of bitter orange for this purpose.
• Anxiety. It is unclear if oral bitter orange or aromatherapy with bitter orange is beneficial in patients with anxiety. Details: Aromatherapy with bitter orange has been evaluated for anxiety in hospitalized or recently hospitalized patients. A clinical study in conscious patients admitted to the intensive care unit shows that inhaling bitter orange as aromatherapy for 30 minutes is associated with lower anxiety scores immediately and 3 hours after the intervention, but not at 1 hour after, when compared with placebo. It is unclear if the improvement from baseline differed between groups; baseline anxiety scores were significantly higher in the placebo group (108752). Another clinical study in adults with acute coronary syndrome shows that aromatherapy with bitter orange essential oil 30% for the 2 days immediately after hospitalization improves anxiety scores by 19%, compared with a 6% improvement in those inhaling placebo (101710). Oral bitter orange has also been evaluated in patients with anxiety. A small clinical study in postmenopausal adults with moderate anxiety shows that taking dried bitter orange flower powder 500 mg orally twice daily for 8 weeks reduces anxiety symptoms by about 4% when compared with placebo, as measured on the State-Trait Anxiety Inventory Scale (97256). However, this improvement is not likely to be considered clinically significant.
• Athletic performance. Several small, short-term clinical studies suggest that oral bitter orange does not improve athletic performance, although some conflicting findings exist. Details: One small clinical study in young males who were former athletes shows that taking 100 mg of p-synephrine from bitter orange extract (Advantra Z, Nutratech Inc.), with or without caffeine 100 mg, daily for 4 days increases the number of total repetitions and volume load by 11% during resistance squat exercise performance when compared with placebo. However, there was no difference in ratings of perceived exertion, and only the p-synephrine plus caffeine group showed an increase in mean power and velocity measures (95683). Other small studies have failed to show a benefit, with or without caffeine. One small study of physically active males with habitual caffeine use shows that taking caffeine 100 mg and bitter orange 100 mg once before exercise does not affect peak power, mean power, total work, or perceived effort or fatigue when compared with placebo (101709). Another small clinical study shows that taking p-synephrine (Synephrine HCL 99%, Nutrition Power) 3 mg/kg orally 60 minutes before exercise does not improve jump tests, 60-meter sprints, or 100-meter sprints in healthy sprint athletes (95655). A small clinical study shows that taking a specific caffeine-containing pre-workout supplement (Cellucor C4 Pre-Workout, Nutrabolt) along with bitter orange extract (Nutratech Inc.) as a single dose 30 minutes before exercise does not improve athletic performance during anaerobic cycling or leg and bench press exercises (95657). Also, taking this combination daily for 8 weeks does not improve strength or body composition when compared with placebo (95656).
• Cancer. Although there has been interest in using oral bitter orange to prevent cancer, there is insufficient reliable information about the clinical effects of bitter orange for this purpose.
• Chronic kidney disease (CKD). Although there has been interest in using oral bitter orange for CKD and other kidney and bladder conditions, there is insufficient reliable information about the clinical effects of bitter orange for these conditions.
• Conjunctivitis. Although there has been interest in using topical bitter orange for conjunctivitis, there is insufficient reliable information about the clinical effects of bitter orange for this purpose.
• Constipation. Although there has been interest in using oral bitter orange for constipation, there is insufficient reliable information about the clinical effects of bitter orange for this purpose.
• Diabetes. Oral bitter orange has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: A very small clinical study in patients with type 2 diabetes shows that drinking a tea made from the leaves of Indian snakeroot and the fruit of bitter orange for 4 months decreases fasting and postprandial glucose levels and glycated hemoglobin (HbA1c) levels when compared with placebo (35751). However, it is unclear if these effects are due to bitter orange, Indian snakeroot, or the combination.
• Diarrhea. Although there has been interest in using oral bitter orange for diarrhea, there is insufficient reliable information about the clinical effects of bitter orange for this purpose.
• Dyspepsia. It is unclear if oral bitter orange is beneficial in patients with dyspepsia. Details: One small clinical trial in patients with functional dyspepsia shows that taking a specific product containing bitter orange in combination with other ingredients (Zhizhu) three times daily for 4 weeks improves symptoms of functional dyspepsia in 67% of patients, compared with 45% of patients taking a similar product containing sweet orange instead of bitter orange (35757).
• Fatigue. Although there has been interest in using oral bitter orange for fatigue, there is insufficient reliable information about the clinical effects of bitter orange for this purpose.
• Flatulence. Although there has been interest in using oral bitter orange for flatulence, there is insufficient reliable information about the clinical effects of bitter orange for this purpose.
• Frostbite. Although there has been interest in using oral bitter orange to prevent frostbite, there is insufficient reliable information about the clinical effects of bitter orange for this purpose.
• Gallbladder disease. Although there has been interest in using oral bitter orange for gallbladder disease, there is insufficient reliable information about the clinical effects of bitter orange for this purpose.
• Headache. Although there has been interest in using topical bitter orange for headache, there is insufficient reliable information about the clinical effects of bitter orange for this purpose.
• Hyperlipidemia. Although there has been interest in using oral bitter orange for hyperlipidemia, there is insufficient reliable information about the clinical effects of bitter orange for this purpose.
• Insomnia. It is unclear if using bitter orange aromatherapy for sleep disturbances is beneficial in postmenopausal or pregnant adults. Details: A small clinical study in postmenopausal adults with sleep disturbances shows that inhaling essential oil of bitter orange 10% as aromatherapy for 5 minutes twice daily for 4 consecutive days each week for 4 weeks does not improve sleep quality when compared with odorless sweet almond oil (108642). Other clinical research in pregnant adults with sleep disturbances shows that inhaling bitter orange essential oil as aromatherapy for 20 minutes twice daily for 1 month improves sleep scores, including sleep duration, latency, and efficiency, when compared with sweet almond oil (110043).
• Obesity. It is unclear if oral bitter orange, or its constituent p-synephrine, is beneficial for obesity. Details: A meta-analysis of clinical trials in adults with or without obesity shows that taking p-synephrine, a constituent of bitter orange, 6-214 mg orally daily for up to 8 weeks does not reduce body weight or fat mass, or alter blood glucose levels, when compared with placebo (109950). Bitter orange has also been studied in combination with other ingredients. One small clinical trial in overweight adults shows that taking a combination of bitter orange 975 mg, caffeine 528 mg, and St. John's wort 900 mg daily along with calorie restriction and exercise reduces body weight when compared with caloric restriction and exercise alone (11268). Another small clinical study in overweight adults shows that taking a specific combination product (Prograde Metabolism, Prograde Nutrition) containing bitter orange, raspberry ketone, caffeine, capsaicin, garlic, ginger, black pepper, cayenne pepper, and chromium along with diet and exercise for 8 weeks reduces body weight, fat mass, and hip and waist girth and increases lean body mass and energy levels when compared with placebo (91291). However, a small clinical trial in overweight and obese adults shows that taking a different combination product (Charge, Labrada), containing bitter orange 150 mg, providing 9 mg synephrine, plus caffeine and several other ingredients twice daily for 8 weeks does not reduce body weight (15381). The effects of bitter orange alone on body weight are unclear.
• Pain (acute). It is unclear if aromatherapy with bitter orange essential oil is beneficial in hospitalized patients with pain. Details: One small clinical trial in conscious patients in intensive care units shows that aromatherapy with bitter orange essential oil for 30 minutes does not reduce pain when compared with placebo (104187).
• Peptic ulcers. Although there has been interest in using oral bitter orange for peptic ulcers, there is insufficient reliable information about the clinical effects of bitter orange for this purpose.
• Premenstrual syndrome (PMS). It is unclear if aromatherapy with bitter orange essential oil is beneficial in patients with PMS. Details: One small clinical trial in healthy female students with PMS shows that inhaling bitter orange blossom 0.5% essential oil as aromatherapy for 5 minutes twice daily for 5 days, starting about one week before menstruation and repeating for two menstrual cycles, improves psychological but not physical symptoms of PMS when compared with aromatherapy with odorless sweet almond oil (98331).
• Pre-procedural anxiety. It is unclear if oral bitter orange or aromatherapy with bitter orange is beneficial for reducing anxiety before surgery. Details: One small clinical study in patients undergoing minor operations shows that taking bitter orange blossom distillate 1 mL/kg two hours prior to surgery reduces preoperative anxiety when compared to baseline. No significant improvements in anxiety were reported in patients taking placebo before surgery (35759). Another small clinical study in patients undergoing coronary angiography shows that inhaling bitter orange essential oil for 15-20 minutes about one hour prior to the procedure reduces anxiety when compared with placebo (104186).
• Pressure ulcers. Although there has been interest in using topical bitter orange for pressure ulcers, there is insufficient reliable information about the clinical effects of bitter orange for this purpose.
• Rheumatoid arthritis (RA). Although there has been interest in using topical bitter orange for RA, there is insufficient reliable information about the clinical effects of bitter orange for this condition.
• Rhinosinusitis. Although there has been interest in using oral bitter orange for rhinosinusitis, there is insufficient reliable information about the clinical effects of bitter orange for this purpose.
• Sexual dysfunction. It is unclear if topical bitter orange oil is beneficial in postmenopausal adults with sexual dysfunction. Details: Preliminary clinical research in postmenopausal adults with sexual dysfunction shows that inhaling bitter orange essential oil 10% as aromatherapy for 5 minutes twice daily, 4 days per week for 4 weeks, improves sexual dysfunction scores by 58% when compared with almond oil. Patients reported improvements in the domains of desire, arousal, lubrication, orgasm, pain, and satisfaction (110042).
• Tinea corporis. It is unclear if topical bitter orange oil is beneficial in patients with tinea corporis. Details: In one small clinical study of patients with either tinea corporis, tina cruris, or tinea pedis, 80% of patients applying a bitter orange oil 25% emulsion three times daily experienced a cure within 1-2 weeks, and 20% experienced a cure within 2-3 weeks. For those applying a solution of bitter orange oil 20% in alcohol, 50% experienced a cure in 1-2 weeks, 30% in 2-3 weeks, and 20% in 3-4 weeks (6972). The validity of these findings is limited by the lack of a comparator group.
• Tinea cruris. It is unclear if topical bitter orange oil is beneficial in patients with tinea cruris. Details: In one small clinical study of patients with either tinea corporis, tina cruris, or tinea pedis, 80% of patients applying a bitter orange oil 25% emulsion three times daily experienced cure within 1-2 weeks, and 20% experienced a cure within 2-3 weeks. For those applying a solution of bitter orange oil 20% in alcohol, 50% experienced a cure in 1-2 weeks, 30% in 2-3 weeks, and 20% in 3-4 weeks (6972). The validity of these findings is limited by the lack of a comparator group.
• Tinea pedis. It is unclear if topical bitter orange oil is beneficial in patients with tinea pedis. Details: In one small clinical study of patients with either tinea corporis, tina cruris, or tinea pedis, 80% of patients applying a bitter orange oil 25% emulsion three times daily experienced cure within 1-2 weeks, and 20% experienced a cure within 2-3 weeks. For those applying a solution of bitter orange oil 20% in alcohol, 50% experienced a cure in 1-2 weeks, 30% in 2-3 weeks, and 20% in 3-4 weeks (6972). The validity of these findings is limited by the lack of a comparator group. More evidence is needed to rate bitter orange for these uses.

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POSSIBLY INEFFECTIVE

• Diabetes. Most research shows that oral Ceylon cinnamon does not benefit patients with type 2 diabetes. Details: Clinical research in adults with well-controlled type 2 diabetes shows that taking Ceylon cinnamon 1-9 grams orally daily for 2-3 months does not improve fasting blood glucose when compared with placebo or a control group (99436,99437,99439). However, one small clinical study in adults with poorly controlled type 2 diabetes despite treatment with metformin showed a trend toward improvement in fasting blood glucose. Taking Ceylon cinnamon 3 grams daily for 8 weeks reduced fasting blood glucose by 12 mg/dL, compared with an increase of 9 mg/dL in those taking placebo. Although this difference was not statistically significant, the study might not have been adequately powered to show a difference. Also, the 8-week duration of this study was too short to reliably assess the effect of Ceylon cinnamon on glycated hemoglobin (HbA1c) (99438). Conversely, a large study clinical study in patients with type 2 diabetes conducted in India shows that taking Ceylon cinnamon 1.5 grams daily for 4 months improves fasting blood glucose by 40 mg/dL and HbA1c by 1% when compared with placebo but does not significantly improve either outcome when compared to baseline (112422). However, it is unclear whether modifications to diabetes medications were allowed during the study.
• Obesity. Preliminary clinical research suggests that oral Ceylon cinnamon does not help with weight loss. Details: Preliminary clinical research shows that drinking black tea steeped with 3 grams of Ceylon cinnamon dried powder three times daily for 8 weeks does not affect weight, waist circumference, or blood pressure when compared with baseline or black tea alone in overweight patients with diabetes (95597). Other preliminary research shows that taking Ceylon cinnamon, titrated up from 85 mg to 500 mg, daily for 3 months has no effect on weight or body mass index, but may reduce hip circumference by 1.8 cm, when compared with baseline in healthy, mostly normal weight adults (97250).

INSUFFICIENT RELIABLE EVIDENCE to RATE

• Allergic rhinitis (hay fever). A nasal spray containing a Ceylon cinnamon extract might improve symptoms of allergic rhinitis. It is unclear if oral Ceylon cinnamon is beneficial. Details: Using a nasal spray containing a polyphenol-rich standardized extract of Ceylon cinnamon 1 mg/mL, twice daily in each nostril for 7 days, reduces the severity of nasal, eye, and nocturnal symptoms, and improves quality of life and work productivity when compared with placebo in people with seasonal allergic rhinitis who are not using any other medications for the condition (103169). One small clinical study in patients with seasonal allergic rhinitis shows that taking a specific combination product (ClearGuard, Access Business Group LLC) containing Ceylon cinnamon extract, acerola fruit concentrate, and powdered Spanish needles (Bidens pilosa) orally, 450 mg three times daily for 3 days, improves nasal symptoms 8 hours after, but not immediately following, a nasal allergen challenge when compared with placebo (23709).
• Chronic obstructive pulmonary disease (COPD). Ceylon cinnamon has only been studied in combination with other ingredients; its effect when used alone is unclear. Details: A moderate-sized clinical study in adults with COPD shows that taking a combination product containing extracts of Ceylon cinnamon, ginger, alpinia, cardamom, and saffron in honey 3 times daily for 8 weeks improves confidence in leaving home and the ratio of forced exploratory volume per second to forced vital capacity of the lungs (FEV1/FVC) when compared with placebo. However, the combination product does not improve most measures of respiratory function or symptoms such as cough, phlegm, chest tightness, dyspnea, reduced energy levels, sleeping disorders, or activity limitations when compared with placebo (111542). It is unclear if these effects are due to Ceylon cinnamon, other ingredients, or the combination.
• Common cold. Although there has been interest in using oral Ceylon cinnamon for the common cold, there is insufficient reliable information about the clinical effects of Ceylon cinnamon for this purpose.
• Denture stomatitis. It is unclear if topical Ceylon cinnamon is beneficial in patients with denture stomatitis. Details: A small clinical trial in patients with denture stomatitis shows that using 10 mL of a mouthwash, as well as a denture spray, containing Ceylon cinnamon essential oil three times daily for 15 days modestly reduces Candida measurements and improves the severity of stomatitis in the oral mucosa and dentures when compared with baseline (108262). The validity of these findings is limited by the lack of a comparator group.
• Diarrhea. Although there has been interest in using oral Ceylon cinnamon for diarrhea, there is insufficient reliable information about the clinical effects of Ceylon cinnamon for this purpose.
• Dysmenorrhea. It is unclear if oral Ceylon cinnamon is beneficial in patients with dysmenorrhea. Details: One preliminary clinical trial in adults with primary dysmenorrhea shows that taking Ceylon cinnamon orally 1 gram three times daily during the first 72 hours of menstruation over the course of two cycles decreases pain by 1.6 points on a 10-point visual analog scale when compared with placebo (99875). The use of a per-protocol analysis limits the validity of these results.
• Dyspepsia. It is unclear if oral Ceylon cinnamon is beneficial in patients with dyspepsia. Details: A small clinical trial in patients with functional dyspepsia shows that taking one capsule of Ceylon cinnamon oil, providing an unspecified dose, three times daily for 6 weeks does not improve symptoms of dyspepsia when compared with sesame oil as placebo (108263).
• Hypertension. It is unclear if oral Ceylon cinnamon is beneficial in patients with prehypertension. Details: A small clinical trial in patients with prehypertension shows that taking Ceylon cinnamon 500 mg three times daily for 90 days does not affect final blood pressure measurements when compared with placebo. However, there was a modest reduction in mean daytime systolic blood pressure when compared with placebo (108261).
• Impaired glucose tolerance (prediabetes). Although there has been interest in using oral Ceylon cinnamon for impaired glucose tolerance, there is insufficient reliable information about the clinical effects of Ceylon cinnamon for this purpose.
• Influenza. Although there has been interest in using oral Ceylon cinnamon for influenza, there is insufficient reliable information about the clinical effects of Ceylon cinnamon for this purpose.
• Intestinal parasite infection. Although there has been interest in using oral Ceylon cinnamon for intestinal parasite infection, there is insufficient reliable information about the clinical effects of Ceylon cinnamon for this purpose.
• Irritable bowel syndrome (IBS). Oral Ceylon cinnamon has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: Preliminary clinical research shows that taking a combination of powdered Ceylon cinnamon 1.5 grams, dried bilberry fruit 10 grams, slippery elm bark 4.5 grams, and agrimony 3 grams orally twice daily for 3 weeks increases the number of bowel movements and reduces symptoms such as abdominal pain, bloating, flatulence, and straining in patients with diarrhea-predominant IBS (35462).
• Migraine headache. It is unclear if oral Ceylon cinnamon is beneficial in patients with migraine headache. Details: Preliminary clinical research shows that taking Ceylon cinnamon powder orally 600 mg three times daily for 2 months, in addition to regular medications for migraine, decreases the frequency, severity, and duration of migraine attacks when compared with placebo (104520).
• Polycystic ovary syndrome (PCOS). It is unclear if oral Ceylon cinnamon is beneficial in patients with PCOS. Details: Taking Ceylon cinnamon orally 1.5 grams daily for 3 months in adults with PCOS does not appear to improve fasting insulin levels, fasting glucose levels, glycated hemoglobin, testosterone, lipid parameters, body weight, or body mass index when compared with placebo (97248). However, a meta-analysis of 5 low-quality studies shows that taking Ceylon cinnamon 0.5-1.5 grams daily for 8 weeks to 1 year reduces insulin resistance and fasting serum insulin levels (104518). Ceylon cinnamon has also been evaluated in combination with other ingredients. Some preliminary clinical research in overweight adults with PCOS shows that taking three tablets of a combination product containing extracts of Ceylon cinnamon, licorice root, peony root, and St. John's wort, providing the equivalent of 750 mg of dried herb for each ingredient, daily for 3 months, plus tribulus extract for 10 days during the follicular phase, in conjunction with lifestyle modification reduces the time between periods by around 43 days when compared with lifestyle modification alone. The rate of conception was four times higher with this combination when compared with control (97216). Another small clinical study shows that taking a mixture of Ceylon cinnamon, spearmint, ginger, and sweet orange daily for 3 months, in addition to clomiphene citrate for 5 days of each menstrual cycle, improves serum antioxidant levels, fasting blood glucose, and serum insulin levels when compared with clomiphene citrate alone. It is unclear whether these changes are associated with an increase in ovulation and pregnancy rates (103168). In both studies, it is unclear if the effects are related to Ceylon cinnamon, other ingredients, or to the combinations used.
• Premature ejaculation. Topical Ceylon cinnamon has only been evaluated in combination with other ingredients; its effect when used alone is unclear. Details: In patients with premature ejaculation, applying a multi-ingredient cream (SS Cream) containing Panax ginseng root, Angelica root, Cistanches deserticola, Zanthoxyl species, Torlidis seed, clove flower, Asiasari root, Ceylon cinnamon, and toad venom to the glans penis one hour prior to intercourse and washing off immediately before intercourse improves ejaculatory latency when compared with placebo (2537). The effects of Ceylon cinnamon alone are unclear. More evidence is needed to rate Ceylon cinnamon for these uses.

(Read more about CEYLON CINNAMON)

LIKELY SAFE ...when used orally in amounts commonly found in foods. Bitter orange has Generally Recognized as Safe (GRAS) status in the US (4912,35751).

POSSIBLY SAFE ...when bitter orange essential oil is used topically or by inhalation as aromatherapy (6972,7107,98331,104186,104187,108642).

POSSIBLY UNSAFE ...when used orally for medicinal purposes. Although single doses of synephrine, or low daily doses used short-term, may be safe in healthy adults (2040,11269,15381,35757,35759,91681,97256,98332), laboratory analyses raise concerns that many marketed bitter orange products contain higher amounts of synephrine and other natural and synthetic amines than on the label, increasing the risk for serious stimulant-related adverse effects (104185). Additionally, there is a lack of agreement regarding a safe daily dose of synephrine. Health Canada has approved 50 mg of p-synephrine daily when used alone, or 40 mg of p-synephrine in combination with up to 320 mg of caffeine daily in healthy adults (91684). The Federal Institute for Risk Assessment in Germany recommends that supplements should provide no more than 6.7 mg of synephrine daily. This recommendation is meant to ensure that patients who frequently consume synephrine in conventional foods will receive no more than 25.7 mg daily (91290). These limits are intended to reduce the risk for serious adverse effects. There have been several case reports of ischemic stroke and cardiotoxicity including tachyarrhythmia, cardiac arrest, syncope, angina, myocardial infarction, ventricular arrhythmia, and death in otherwise healthy patients who have taken bitter orange extract alone or in combination with other stimulants such as caffeine (2040,6979,12030,13039,13067,14326,14342,91680).

PREGNANCY AND LACTATION: LIKELY SAFE
when used orally in the amounts found in foods. Bitter orange has Generally Recognized as Safe (GRAS) status in the US (4912).

PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally for medicinal purposes. There are case reports of cardiotoxicity including tachyarrhythmia, syncope, and myocardial infarction in otherwise healthy adults who have taken bitter orange extract alone or in combination with other stimulants such as caffeine (2040,6979,12030,13039,13067,14326,14342,91680). The effects of bitter orange during lactation are unknown; avoid use.

(Read more about BITTER ORANGE)

LIKELY SAFE ...when consumed in amounts commonly found in foods. Ceylon cinnamon has Generally Recognized As Safe (GRAS) status in the US for use as a spice or flavoring agent (4912).

POSSIBLY SAFE ...when used orally and appropriately in medicinal amounts. Ceylon cinnamon 0.5-3 grams daily has been safely used in studies lasting up to 6 months (4,12,97248,97250,99874). ...when used as a mouth rinse for up to 15 days (92071). There is insufficient reliable information available about the safety of Ceylon cinnamon when used orally in greater amounts or for longer periods. Ceylon cinnamon contains trace amounts of coumarin (108260). In very high doses, coumarin can cause hepatotoxicity (15302). However, since the amount of coumarin in Ceylon cinnamon is negligible, it is unlikely to cause toxic effects (89652,92072,92073).

PREGNANCY: LIKELY SAFE
when consumed in amounts commonly found in foods (4912).

PREGNANCY: LIKELY UNSAFE
when used orally in amounts greater than those found in foods. Fetal abnormalities have been reported in animals (4,12).

LACTATION: LIKELY SAFE
when consumed in amounts commonly found in foods (4912). There is insufficient reliable information available about the safety of Ceylon cinnamon in amounts greater than those found in foods.

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ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, bitter orange might increase the risk of hypoglycemia when taken with antidiabetes drugs.  Details Some clinical research shows that drinking a tea containing bitter orange and Indian snakeroot reduces fasting and postprandial glucose levels in patients with type 2 diabetes who are using antidiabetes drugs (35751). However, it is unclear if these effects are due to bitter orange, Indian snakeroot, or the combination. An animal study also shows that p-synephrine in combination with gliclazide , a sulfonylurea, causes an additional 20% to 44% decrease in glucose levels when compared with gliclazide alone (95658).

CAFFEINE Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = B Bitter orange might increase blood pressure and heart rate when taken with caffeine.  Details Small clinical studies show that taking bitter orange in combination with caffeine can increase blood pressure and heart rate in otherwise healthy normotensive adults (13657,95659). Theoretically, this might increase the risk of serious cardiovascular adverse effects.

COLCHICINE Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Bitter orange might affect colchicine levels.  Details Colchicine is a substrate of P-glycoprotein and cytochrome P450 3A4 (CYP3A4). Bitter orange has been reported to inhibit CYP3A4 and increase levels of CYP3A4 substrates (7029,11362,93470). However, one small clinical study in healthy adults shows that drinking bitter orange juice 240 mL twice daily for 4 days and taking a single dose of colchicine 0.6 mg on the 4th day decreases colchicine peak serum levels by 24%, time to peak serum level by 1 hour, and overall exposure to colchicine by 20% (35762). The clinical significance of this finding is unclear.

CYTOCHROME P450 2D6 (CYP2D6) SUBSTRATES Interaction Rating = Minor Be watchful with this combination. Severity = Mild •  Occurrence = Possible •  Level of Evidence = D Theoretically, bitter orange might increase levels of drug metabolized by CYP2D6.  Details In vitro research shows that octopamine, a constituent of bitter orange, weakly inhibits CYP2D6 enzymes (91878). This effect has not been reported in humans.

CYTOCHROME P450 3A4 (CYP3A4) SUBSTRATES Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Bitter orange might increase levels of drugs metabolized by CYP3A4.  Details Small clinical studies suggest that single or multiple doses of freshly squeezed bitter orange juice 200-240 mL can inhibit CYP3A4 metabolism of drugs (7029,11362,93470), causing increased drug levels and potentially increasing the risk of adverse effects. However, the extent of the effect of bitter orange on CYP3A4-mediated drug interactions is unknown. Some evidence suggests that bitter orange selectively inhibits intestinal CYP3A4, but not hepatic CYP3A4. Its effect on P-glycoprotein, which strongly overlaps with CYP3A4 interactions, is unclear (7029,11269,11270,11362). One small clinical study shows that drinking 8 ounces of freshly squeezed bitter orange juice has no effect on cyclosporine, which seems to be more dependent on hepatic CYP3A4 and P-glycoprotein than intestinal CYP3A4 (11270).

DEXTROMETHORPHAN (Robitussin DM, others) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Bitter orange might increase blood levels of dextromethorphan.  Details One small clinical study shows that bitter orange juice increases dextromethorphan levels, likely through cytochrome P450 3A4 (CYP3A4) inhibition (11362). Theoretically, bitter orange might increase the risk for dextromethorphan-related adverse effects.

FELODIPINE (Plendil) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Bitter orange might increase blood levels of felodipine.  Details One small clinical study shows that bitter orange juice increases felodipine levels, likely through cytochrome P450 3A4 (CYP3A4) inhibition (7029). Theoretically, bitter orange might increase the risk for felodipine-related adverse effects.

INDINAVIR (Crixivan) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Bitter orange might increase blood levels of indinavir.  Details One small clinical study shows that bitter orange juice slightly increases indinavir levels, but this effect is likely to be clinically insignificant. Bitter orange selectively inhibits intestinal cytochrome P450 3A4 (CYP3A4); however, the metabolism of indinavir seems to be more dependent on hepatic CYP3A4 (11269). The effect of bitter orange on other protease inhibitors has not been studied.

MIDAZOLAM (Versed) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = B Bitter orange might increase blood levels of midazolam.  Details One small clinical study shows that bitter orange juice can increase midazolam levels, likely through inhibition of cytochrome P450 3A4 (CYP3A4) (7029). Theoretically, bitter orange might increase the risk of midazolam-related adverse effects.

MONOAMINE OXIDASE INHIBITORS (MAOIs) Interaction Rating = Major Do not take this combination. Severity = High •  Occurrence = Probable •  Level of Evidence = D Theoretically, taking MAOIs with synephrine-containing bitter orange preparations might increase the hypertensive effects of synephrine, potentially leading to hypertensive crisis.  Details Bitter orange contains tyramine, octopamine, and synephrine, which are MAO substrates (11267,11995,12378).

QT INTERVAL-PROLONGING DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = High •  Occurrence = Possible •  Level of Evidence = D Theoretically, bitter orange might have an additive effect when combined with drugs that prolong the QT interval, potentially increasing the risk of ventricular arrhythmias.  Details One case report suggests that taking bitter orange in combination with other stimulants such as caffeine might prolong the QT interval in some patients (13039).

SILDENAFIL (Viagra) Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Probable •  Level of Evidence = B Bitter orange juice might increase blood levels of sildenafil.  Details A small clinical study in healthy adult males shows that drinking freshly squeezed bitter orange juice 250 mL daily for 3 days and taking a single dose of sildenafil 50 mg on the 3rd day increases the peak plasma concentration of sildenafil by 18% and the overall exposure to sildenafil by 44%. Theoretically, this may be due to inhibition of cytochrome P450 3A4 by bitter orange (93470).

STIMULANT DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = B Theoretically, bitter orange might increase the risk of hypertension and adverse cardiovascular effects when taken with stimulant drugs.  Details Bitter orange appears to have stimulant effects (2040,6979).

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ANTIDIABETES DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, Ceylon cinnamon may have additive effects with antidiabetes drugs.  Details Ceylon cinnamon may lower blood glucose levels (11247,11248,11973). Dose adjustments might be necessary.

ANTIHYPERTENSIVE DRUGS Interaction Rating = Moderate Be cautious with this combination. Severity = Moderate •  Occurrence = Possible •  Level of Evidence = D Theoretically, Ceylon cinnamon might have additive effects with antihypertensive drugs and increase the risk of hypotension.  Details Animal research shows that Ceylon cinnamon extract has vasorelaxant properties and reduces blood pressure in rat models of hypertension, possibly via inhibition of calcium influx through L-type voltage-sensitive channels (92085,92086).

(Read more about CEYLON CINNAMON)

General ...Orally, bitter orange might be unsafe when used in medicinal amounts. Topically and when inhaled as aromatherapy, bitter orange seems to be well tolerated.
Most Common Adverse Effects:
Orally: Hypertension and tachycardia, particularly when used in combination with caffeine and/or other stimulant ingredients.
Topically: Skin irritation.
Serious Adverse Effects (Rare):
Orally: Myocardial infarction, QT prolongation, seizures, stroke, syncope, tachyarrhythmia, and ventricular fibrillation have been reported in patients taking bitter orange in combination with other ingredients. It is unclear if these effects are due to bitter orange, other ingredients, or the combination.

Cardiovascular ...Bitter orange, which contains adrenergic agonists synephrine and octopamine, may cause hypertension and cardiovascular toxicity when taken orally (2040,6969,6979). Studies evaluating the effect of bitter orange on cardiovascular parameters have been mixed. Several studies show that taking bitter orange alone or in combination with caffeine increases blood pressure and heart rate. In one clinical study, bitter orange in combination with caffeine increased systolic and diastolic blood pressure and heart rate in otherwise healthy normotensive adults (13657). In another study, a single dose of bitter orange 900 mg, standardized to 6% synephrine (54 mg), also increased systolic and diastolic blood pressure and heart rate for up to 5 hours in young, healthy adults (13774). Using half that dose of bitter orange and providing half as much synephrine, did not seem to significantly increase blood pressure or QT interval in healthy adults (14311). Increased diastolic, but not systolic, blood pressure or heart rate also occurred in a clinical trial involving a specific supplement containing synephrine 21 mg and caffeine 304 mg (Ripped Fuel Extreme Cut, Twinlab) (35743). Synephrine given intravenously to males increased systolic blood pressure, but lacked an effect on diastolic blood pressure or heart rate (12193).
In clinical research and case reports, tachycardia, tachyarrhythmia, QT prolongation, ischemic stroke, variant angina, and myocardial infarction have occurred with use of bitter orange or synephrine-containing multi-ingredient products (12030,13039,13067,13091,13657,14326,35749,91680). In one case report, a combination product containing bitter orange may have masked bradycardia and hypotension while exacerbating weight loss in a 16 year-old female with an eating disorder taking the product for weight loss (35740). From 1998 to 2004, Health Canada received 16 reports of serious adverse cardiovascular reactions such as tachycardia, cardiac arrest, ventricular fibrillation, blackout, and collapse. In two of these cases, the patient died. In almost all of these cases, bitter orange was combined with another stimulant such as caffeine, ephedrine, or both (14342).
Other research has found no significant effect of bitter orange on blood pressure or heart rate. Several clinical studies have reported that, when taken as a single dose or in divided doses ranging from 20-100 mg for one day, p-synephrine had no significant effect on blood pressure, heart rate, electrocardiogram results or adverse cardiovascular events in healthy adults (35772,91681,91681,95659,101708) Similarly, no difference in blood pressure, heart rate or electrocardiogram results were reported when p-synephrine from bitter orange (Advantra Z/Kinetic; Nutratech/Novel Ingredients Inc.) was taken for 6 weeks in healthy patients (11268). Another clinical study showed no significant effect of bitter orange (Nutratech Inc.), standardized to synephrine 20 mg, on blood pressure or heart rate when taken daily for 8 weeks in healthy males (95656). In other research, changes in blood pressure, heart rate, or QTc interval were lacking when bitter orange was given alone or in combination with caffeine and green tea (14311,35753,35755,35764,35769,35770). In one study of healthy adults, taking a single dose of p-synephrine 103 mg actually reduced mean diastolic blood pressure by 0.4-4 mmHg at 1 and 2 hours after administration when compared with placebo (95659).
A meta-analysis of clinical trials in adults with or without obesity suggests that taking p-synephrine 6-214 mg orally daily does not affect blood pressure or heart rate when used short-term, but modestly increases blood pressure and heart rate when taken for 56-60 days (109950).
The effect of bitter orange on blood pressure, heart rate, and electrocardiogram results in patients with underlying conditions, particularly cardiovascular disease, is unknown and requires further study.

Dermatologic ...Photosensitivity may occur, particularly in fair-skinned people (11909). In a clinical trial, topical application with bitter orange essential oil resulted in irritation (6972).

Endocrine ...Some clinical research shows that taking a specific supplement containing 21 mg of synephrine and 304 mg of caffeine (Ripped Fuel Extreme Cut, Twinlab) increases levels of postprandial glucose (35743). Other preliminary clinical research shows that taking a specific pre-workout supplement (Cellucor C4 Pre-Workout, Nutrabolt) along with a bitter orange extract standardized for synephrine 20 mg (Nutratech Inc.) 30 minutes once before exercise causes a significant 12% increase in glucose (95657); however, there is no difference in blood glucose when compared with placebo when this combination is taken daily for 8 weeks (95656). The effect of bitter orange itself is unclear.

Gastrointestinal ...Bitter orange has been linked to a report of ischemic colitis. In one case, a 52-year-old female developed ischemic colitis after taking a bitter orange-containing supplement (NaturalMax Skinny Fast, Nutraceutical Corporation) for a week. Symptoms resolved within 48 hours after discontinuing the supplement (15186). As this product contains various ingredients, the effect of bitter orange itself is unclear.

Musculoskeletal ...Unsteady gait has been noted in one case report of a patient taking bitter orange (13091). In another case, an otherwise healthy, Black male with sickle cell trait, developed severe rhabdomyolysis following ingestion of a specific weight loss product (Lipo 6, Nutrex Research Inc.), which contained synephrine and caffeine (16054). However, other preliminary clinical research shows that taking a specific pre-workout supplement (Cellucor C4 Pre-Workout, Nutrabolt) along with a bitter orange extract standardized for synephrine 20 mg (Nutratech Inc.), taken 30 minutes once before exercise (95657) or daily for 8 weeks, does not affect creatine kinase or serum creatinine levels when compared with placebo (95656). As these products contain various ingredients, the effect of bitter orange itself is unclear.

Neurologic/CNS ...Dizziness, difficulty in concentrating, memory loss, syncope, seizure, and stroke have been noted in case reports following bitter orange administration (13091,13039). Theoretically, bitter orange may trigger a migraine or cluster headache due to its synephrine and octopamine content (35768). When used as aromatherapy, bitter orange essential oil has also been reported to cause headache in some patients (104187). Sprint athletes taking the bitter orange constituent p-synephrine 3 mg/kg (Synephrine HCL 99%, Nutrition Power) 60 minutes before exercises and sprinting reported more nervousness (mean difference 0.9) when compared with placebo on a Likert scale. Although statistically significant, this difference is not considered clinically significant (95655).

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General ...Orally, Ceylon cinnamon is generally well tolerated, and adverse reactions are uncommon.
Most Common Adverse Effects:
Orally: Bloating, dyspepsia, nausea.
Topically: Allergic dermatitis, irritation of mucous membranes and skin.

Dermatologic ...Orally, a case of systemic contact dermatitis has been reported in a patient who consumed cinnamon (type not specified) after being previously sensitized to cinnamyl alcohol via cutaneous exposure (95599). In a small study of oral Ceylon cinnamon, two patients reported itching (104520). In another small study, two patients reported rashes (108263).
Topically, cinnamon oil can cause skin irritation and allergic dermatitis, probably due to cinnamaldehyde which makes up 60% to 80% of cinnamon oil (2537,12635,92071,95596,95599). In one case report, a 16-year-old female experienced worsening dermatitis after using a homemade facial scrub containing cinnamon powder (type not specified). Symptoms improved after discontinuation of the scrub (95596). Several cases of intraoral allergic contact dermatitis have been reported in patients consuming cinnamon (type not specified) or using products containing constituents of cinnamon (95598).

Gastrointestinal ...Orally, gastrointestinal side effects such as heartburn, nausea, bloating, and dyspepsia have been reported (97250).

Hematologic ...Orally, a case of postoperative hemorrhage is reported in a 49-year-old patient after taking Ceylon cinnamon 1 tablespoon daily for 10 months. One day post-colectomy, the patient had an INR of 1.59 and intraabdominal bleeding that required exploratory laparotomies, blood transfusion, and fresh frozen plasma. Ultimately, the patient was discharged (112421).

Hepatic ...While there is concern about the coumarin content in cassia cinnamon increasing the risk for hepatic adverse effects and bleeding, the amount of coumarin in Ceylon cinnamon is negligible and unlikely to cause toxic effects (89652,92072,92073). In one case report, a 73-year-old female taking rosuvastatin for several months developed elevated liver function tests (LFTs), abdominal pain, nausea, and vomiting after taking cinnamon (unknown dose and type) for 7 days. The acute hepatitis and elevated LFTs resolved after stopping both cinnamon and rosuvastatin. The patient was later able to resume rosuvastatin without recurrence (97249).

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