Each capsule contains: Quercetin (3,3',4',5,7-pentahydroxyflavone) 100 mg • Citrus aurantium (27% bioflavonoids) 50 mg • Rosa canina 50 mg • Vaccinium myrtillus 120:1 extract (DHE: 6000 mg) 50 mg • Vitamin C 500 mg. Other Ingredients: Colloidal Silicon Dioxide, Hypromellose, Magnesium Stearate, Microcrystalline Cellulose.
Brand name products often contain multiple ingredients. To read detailed information about each ingredient, click on the link for the individual ingredient shown above.
In 2004, Canada began regulating natural medicines as a category of products separate from foods or drugs. These products are officially recognized as "Natural Health Products." These products include vitamins, minerals, herbal preparations, homeopathic products, probiotics, fatty acids, amino acids, and other naturally derived supplements.
In order to be marketed in Canada, natural health products must be licensed. In order to be licensed in Canada, manufacturers must submit applications to Health Canada including information about uses, formulation, dosing, safety, and efficacy.
Products can be licensed based on several criteria. Some products are licensed based on historical or traditional uses. For example, if an herbal product has a history of traditional use, then that product may be acceptable for licensure. In this case, no reliable scientific evidence is required for approval.
For products with non-traditional uses, some level of scientific evidence may be required to support claimed uses. However, a high level of evidence is not necessarily required. Acceptable sources of evidence include at least one well-designed, randomized, controlled trial; well-designed, non-randomized trials; cohort and case control studies; or expert opinion reports.
Finished products licensed by Health Canada must be manufactured according to Good Manufacturing Practices (GMPs) as outlined by Health Canada.
Synephrine/Bitter Orange This product contains the ingredient synephrine. Synephrine is a stimulant similar to ephedrine, which is contained in the herb ephedra (ma huang). Ephedra products were removed from the U.S. market due to safety concerns. Ephedra is linked to stroke, heart attack, seizure, and other serious side effects. Many manufacturers have now substituted synephrine in products that used to contain ephedra. These products are typically promoted for weight loss. Many of these products are now labeled as ephedra-free or ma huang-free, but they often still contain the stimulant synephrine. These synephrine-containing products likely have the same risks as the ephedra-containing products. Synephrine is a constituent of the bitter orange (Citrus aurantium). Products that list bitter orange or Citrus aurantium on the label also likely contain synephrine. Advise patients about the potential risks associated with this and other synephrine-containing products.
Below is general information about the effectiveness of the known ingredients contained in the product Vitamin C Complex. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
INSUFFICIENT RELIABLE EVIDENCE to RATE
INSUFFICIENT RELIABLE EVIDENCE to RATE
INSUFFICIENT RELIABLE EVIDENCE to RATE
INSUFFICIENT RELIABLE EVIDENCE to RATE
INSUFFICIENT RELIABLE EVIDENCE to RATE
Below is general information about the safety of the known ingredients contained in the product Vitamin C Complex. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
LIKELY SAFE ...when used orally and appropriately in amounts commonly found in foods. Bilberry has Generally Recognized As Safe status (GRAS) for use in foods in the US (4912).
POSSIBLY SAFE ...when used orally and appropriately for medicinal purposes. Bilberry fruit extracts have been used with apparent safety in clinical trials at a dose of up to 160 mg daily for up to 6 months (39,40,8139,9739,14280,35472,35510,35512,103190,104192,104195). A higher bilberry extract dose of 1.4 grams daily has been used with apparent safety for up to 4 weeks (104194). Whole bilberries or bilberry juice have also been consumed with apparent safety in quantities of 100-160 grams daily for up to 35 days (35463,91506).
POSSIBLY UNSAFE ...when the leaves are used orally in high doses or for a prolonged period. Death can occur with chronic use of 1.5 gram/kg daily (2).
PREGNANCY AND LACTATION: LIKELY SAFE
when used orally in the amounts commonly found in foods.
However, there is insufficient reliable information available about the safety of bilberry when used in medicinal amounts during pregnancy and lactation; avoid using.
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.
POSSIBLY SAFE ...when used orally and appropriately, short-term. Quercetin has been used with apparent safety in doses up to 1 gram daily for up to 12 weeks (481,1998,1999,16418,16429,16430,16431,96774,96775,96782)(99237,102539,102540,102541,104229,104679,106498,106499,107450,109620)(109621). ...when used intravenously and appropriately. Quercetin has been used with apparent safety in doses less than 945 mg/m2. Higher doses have been reported to cause nephrotoxicity (9564,16418). There is insufficient reliable information available about the safety of quercetin when used topically.
POSSIBLY UNSAFE ...when used intravenously in large amounts. Doses greater than 945 mg/m2 have been reported to cause nephrotoxicity (9564,16418).
PREGNANCY AND LACTATION:
Insufficient reliable information available; avoid using.
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.
LIKELY SAFE ...when used orally, topically, intramuscularly, or intravenously and appropriately. Vitamin C is safe when taken orally in doses below the tolerable upper intake level (UL). Tell patients not to exceed the UL of 2000 mg daily (1959,4713,4714,4844). ...when used intravenously or intramuscularly and appropriately. Injectable vitamin C is an FDA-approved prescription product (15).
POSSIBLY UNSAFE ...when used orally in excessive doses. Doses greater than the tolerable upper intake level (UL) of 2000 mg daily can significantly increase the risk of adverse effects such as osmotic diarrhea and gastrointestinal upset (4844).
CHILDREN: LIKELY SAFE
when used orally and appropriately (4844,10352,14443).
CHILDREN: POSSIBLY UNSAFE
when used orally in excessive amounts.
Tell patients not to use doses above the tolerable upper intake level (UL) of 400 mg daily for children ages 1 to 3 years, 650 mg daily for children 4 to 8 years, 1200 mg daily for children 9 to 13 years, and 1800 mg daily for adolescents 14 to 18 years. Higher doses can cause osmotic diarrhea and gastrointestinal upset (4844).
PREGNANCY AND LACTATION: LIKELY SAFE
when used orally and appropriately (4844).
PREGNANCY AND LACTATION: POSSIBLY UNSAFE
when used orally in excessive doses.
Tell patients over age 19 not to use doses exceeding the UL of 2000 mg daily when pregnant or breast-feeding and for those 14-18 years of age not to use doses exceeding 1800 mg daily when pregnant or breast-feeding. Higher doses can cause osmotic diarrhea and gastrointestinal upset. Large doses of vitamin C during pregnancy can also cause newborn scurvy (4844); avoid using.
Below is general information about the interactions of the known ingredients contained in the product Vitamin C Complex. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
Theoretically, bilberry fruit extract might increase the risk of bleeding when taken with anticoagulant or antiplatelet drugs.
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Theoretically, bilberry leaf or fruit extract may increase the risk of hypoglycemia when taken with antidiabetes drugs.
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Animal research suggests that bilberry leaf extract might have blood glucose-lowering activity (1264). Also, one small clinical trial in patients with type 2 diabetes shows that taking bilberry fruit extract 470 mg as a single dose prior to an oral glucose tolerance test lowers plasma glucose levels when compared with placebo (91507).
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Theoretically, bilberry fruit extract might decrease levels of drugs metabolized by CYP2E1.
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Animal research shows that exposure to small concentrations of bilberry extract in drinking water for around one month increased CYP2E1 activity by 31%. However, exposure over a 2-month period did not increase CYP2E1 activity (103191). This effect has not been reported in humans.
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Theoretically, bilberry fruit extract might reduce the efficacy of erlotinib.
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In vitro research suggests that bilberry fruit extract and its constituents, delphinidin and delphinidin-3-O-glucoside, inhibit the activity of erlotinib (97031). This interaction has not been reported in humans.
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Theoretically, bitter orange might increase the risk of hypoglycemia when taken with antidiabetes drugs.
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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).
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Bitter orange might increase blood pressure and heart rate when taken with caffeine.
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Bitter orange might affect colchicine levels.
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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.
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Theoretically, bitter orange might increase levels of drug metabolized by CYP2D6.
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In vitro research shows that octopamine, a constituent of bitter orange, weakly inhibits CYP2D6 enzymes (91878). This effect has not been reported in humans.
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Bitter orange might increase levels of drugs metabolized by CYP3A4.
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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).
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Bitter orange might increase blood levels of dextromethorphan.
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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.
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Bitter orange might increase blood levels of felodipine.
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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.
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Bitter orange might increase blood levels of indinavir.
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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.
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Bitter orange might increase blood levels of midazolam.
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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.
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Theoretically, taking MAOIs with synephrine-containing bitter orange preparations might increase the hypertensive effects of synephrine, potentially leading to hypertensive crisis.
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Theoretically, bitter orange might have an additive effect when combined with drugs that prolong the QT interval, potentially increasing the risk of ventricular arrhythmias.
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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).
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Bitter orange juice might increase blood levels of sildenafil.
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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).
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Theoretically, bitter orange might increase the risk of hypertension and adverse cardiovascular effects when taken with stimulant drugs.
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Theoretically, concomitant use of quercetin and antidiabetes drugs might increase the risk of hypoglycemia.
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Clinical research suggests that a combination of quercetin, myricetin, and chlorogenic acid reduce levels of fasting glucose in patients with type 2 diabetes, including those already taking antidiabetes agents (96779). The effect of quercetin alone is unknown. |
Theoretically, taking quercetin with antihypertensive drugs might increase the risk of hypotension.
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Theoretically, concomitant use might increase the levels and adverse effects of cyclosporine.
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A small study in healthy volunteers shows that pretreatment with quercetin increases plasma levels and prolongs the half-life of a single dose of cyclosporine, possibly due to inhibition of p-glycoprotein or cytochrome P450 3A4 (CYP3A4), which metabolizes cyclosporin (16434). |
Theoretically, concomitant use might increase the levels and adverse effects of CYP2C8 substrates.
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Theoretically, concomitant use might increase the levels and adverse effects of CYP2C9 substrates.
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A small clinical study in healthy volunteers shows that taking quercetin 500 mg twice daily for 10 days prior to taking diclofenac, a CYP2C9 substrate, increases diclofenac plasma levels by 75% and prolongs the half-life by 32.5% (97931). Animal research also shows that pretreatment with quercetin increases plasma levels and prolongs the half-life of losartan (Cozaar), a substrate of CYP2C9 (100968). Furthermore, laboratory research shows that quercetin inhibits CYP2C9 (15549,16433). |
Theoretically, concomitant use might increase the levels and adverse effects of CYP2D6 substrates.
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Theoretically, concomitant use might alter the effects and adverse effects of CYP3A4 substrates.
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A small clinical study in healthy volunteers shows that pretreatment with quercetin increases plasma levels and prolongs the half-life of a single dose of cyclosporine (Neoral, Sandimmune), a substrate of CYP3A4 (16434). Animal research also shows that pretreatment with quercetin increases plasma levels and prolongs the half-life of losartan (Cozaar) and quetiapine (Seroquel), substrates of CYP3A4 (100968,104228). Other laboratory research also shows that quercetin inhibits CYP3A4 (15549,16433,16435). However, one clinical study shows that quercetin can increase the metabolism of midazolam, a substrate of CYP3A4, and decrease serum concentrations of midazolam by about 24% in some healthy individuals, suggesting possible induction of CYP3A4 (91573).
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Theoretically, concomitant use might increase the levels and adverse effects of diclofenac.
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A small clinical study in healthy volunteers shows that taking quercetin 500 mg twice daily for 10 days prior to taking diclofenac increases diclofenac plasma levels by 75% and prolongs the half-life by 32.5%. This is thought to be due to inhibition of CYP2C9 by quercetin (97931). |
Theoretically, concomitant use might increase the effects and adverse effects of losartan and decrease the effects of its active metabolite.
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Animal research shows that pretreatment with quercetin increases plasma levels and prolongs the half-life of losartan (Cozaar) while decreasing plasma levels of losartan's active metabolite. This metabolite, which is around 10-fold more potent than losartan, is the result of cytochrome P450 (CYP) 2C9- and CYP3A4-mediated transformation of losartan. Additionally, in vitro research shows that quercetin may inhibit P-glycoprotein-mediated efflux of losartan from the intestines, resulting in increased absorption of losartan (100968). These results suggest that concomitant use of quercetin and losartan might increase systemic exposure to losartan while also decreasing plasma concentrations of losartan's active and more potent metabolite. |
Theoretically, concomitant use might decrease the levels and effects of midazolam.
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A small clinical study in healthy volunteers shows that quercetin can increase the metabolism of midazolam, with a decrease in AUC of about 24% (91573). |
Theoretically, quercetin might increase the effects and adverse effects of mitoxantrone.
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In vitro research shows that quercetin increases the intracellular accumulation and cytotoxicity of mitoxantrone, possibly through inhibition of breast cancer resistance protein (BCRP), of which mitoxantrone is a substrate (107897). So far, this interaction has not been reported in humans.
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Theoretically, concomitant use might increase the effects and adverse effects of OAT1 substrates.
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In vitro research shows that quercetin is a strong non-competitive inhibitor of OAT1, with half-maximal inhibitory concentration (IC50) values less than 10 mcM (104454). So far, this interaction has not been reported in humans. |
Theoretically, concomitant use might increase the effects and adverse effects of OAT3 substrates.
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Theoretically, concomitant use might increase the effects and adverse effects of OATP substrates.
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In vitro evidence shows that quercetin can inhibit organic anion-transporting peptide (OATP) 1B1-mediated uptake of estrone-3-sulfate and pravastatin (91581). Furthermore, clinical research in healthy males shows that intake of quercetin along with pravastatin increases the AUC of pravastatin by 24%, prolongs its half-life by 14%, and decreases its apparent clearance by 18%, suggesting that quercetin modestly inhibits the uptake of pravastatin in hepatic cells (91581). |
Theoretically, concomitant use might alter the effects and adverse effects of P-glycoprotein substrates.
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There is preliminary evidence that quercetin inhibits the gastrointestinal P-glycoprotein efflux pump, which might increase the bioavailability and serum levels of drugs transported by the pump (16433,16434,16435,100968,104228). A small study in healthy volunteers reported that pretreatment with quercetin increased bioavailability and plasma levels after a single dose of cyclosporine (Neoral, Sandimmune) (16434). Also, two small studies have shown that quercetin might decrease the absorption of talinolol, a substrate transported by the gastrointestinal P-glycoprotein efflux pump (91579,91580). However, in another small study, several days of quercetin treatment did not significantly affect the pharmacokinetics of saquinavir (Invirase) (16433). The reason for these discrepancies is not entirely clear (91580). Until more is known, use quercetin cautiously in combination with P-glycoprotein substrates. |
Theoretically, concomitant use might increase the effects and adverse effects of pravastatin.
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In vitro evidence shows that quercetin can inhibit OATP 1B1-mediated uptake of pravastatin (91581). Also, preliminary clinical research in healthy males shows that intake of quercetin along with pravastatin increases the maximum concentration of pravastatin by 24%, prolongs its half-life by 14%, and decreases its apparent clearance by 18%, suggesting that quercetin modestly inhibits the uptake of pravastatin in hepatic cells (91581).
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Theoretically, quercetin might increase the effects and adverse effects of prazosin.
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In vitro research shows that quercetin inhibits the transcellular efflux of prazosin, possibly through inhibition of breast cancer resistance protein (BCRP), of which prazosin is a substrate. BCRP is an ATP-binding cassette efflux transporter in the intestines, kidneys, and liver (107897). So far, this interaction has not been reported in humans.
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Theoretically, concomitant use might increase the effects and adverse effects of quetiapine.
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Animal research shows that pretreatment with quercetin can increase plasma levels of quetiapine and prolong its clearance, possibly due to inhibition of cytochrome P450 3A4 (CYP3A4) by quercetin. Additionally, the brain-to-plasma ratio of quetiapine concentrations increased, possibly due to inhibition of P-glycoprotein at the blood-brain barrier (104228). This interaction has not been reported in humans.
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Theoretically, concomitant use might inhibit the effects of quinolone antibiotics.
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In vitro, quercetin binds to the DNA gyrase site on bacteria (481), which may interfere with the activity of quinolone antibiotics.
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Theoretically, quercetin might increase the effects and adverse effects of sulfasalazine.
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Animal research shows that quercetin increases the maximum serum concentration (Cmax) and area under the curve (AUC) of sulfasalazine, possibly through inhibition of breast cancer resistance protein (BCRP), of which sulfasalazine is a substrate (107897). So far, this interaction has not been reported in humans.
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Theoretically, quercetin may increase the risk of bleeding if used with warfarin.
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Animal and in vitro studies show that quercetin might increase serum levels of warfarin (17213,109619). Quercetin and warfarin have the same human serum albumin (HSA) binding site, and in vitro research shows that quercetin has stronger affinity for the HSA binding site and can theoretically displace warfarin, causing higher serum levels of warfarin (17213). Animal research shows that taking quercetin for 2 weeks before initiating warfarin increases the maximum serum level of warfarin by 30%, the half-life by 10%, and the overall exposure by 63% when compared with control. Concomitant administration of quercetin and warfarin, without quercetin pre-treatment, also increased these measures, but to a lesser degree. Researchers theorize that inhibition of CYP3A4 by quercetin may explain these effects (109619). So far, this interaction has not been reported in humans.
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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.
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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.
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Theoretically, rose hip might increase the amount of aluminum absorbed from aluminum compounds.
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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.
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Theoretically, rose hip might reduce the effectiveness of anticoagulant or antiplatelet drugs.
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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.
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Theoretically, the antioxidant effects of rose hip might reduce the effectiveness of antitumor antibiotics.
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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.
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Theoretically, rose hip might reduce the clearance of aspirin; however, its vitamin C content is likely too low to produce clinically significant effects.
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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.
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Theoretically, rose hip might increase blood levels of estrogens.
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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).
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Theoretically, rose hip might increase blood levels of lithium.
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Theoretically, rose hip might reduce the effectiveness of warfarin; however, its vitamin C content is likely too low to produce clinically significant effects.
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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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High-dose vitamin C might slightly prolong the clearance of acetaminophen.
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A small pharmacokinetic study in healthy volunteers shows that taking high-dose vitamin C (3 grams) 1.5 hours after taking acetaminophen 1 gram slightly increases the apparent half-life of acetaminophen from around 2.3 hours to 3.1 hours. Ascorbic acid competitively inhibits sulfate conjugation of acetaminophen. However, to compensate, elimination of acetaminophen glucuronide and unconjugated acetaminophen increases (6451). This effect is not likely to be clinically significant.
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Theoretically, antioxidant effects of vitamin C might reduce the effectiveness of alkylating agents.
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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). More evidence is needed to determine what effect, if any, antioxidants such as vitamin C have on chemotherapy.
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Vitamin C can increase the amount of aluminum absorbed from aluminum compounds.
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Research in animals and humans shows that vitamin C increases aluminum absorption, theoretically by chelating aluminum and keeping it in solution where it is available for absorption (10549,10550,10551,21556). In people with normal renal function, urinary excretion of aluminum will likely increase, making aluminum retention and toxicity unlikely (10549). Patients with renal failure who take aluminum-containing compounds such as phosphate binders should avoid vitamin C supplements in doses above the recommended dietary allowances.
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Theoretically, the antioxidant effects of vitamin C might reduce the effectiveness of antitumor antibiotics.
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The use of antioxidants like vitamin C during chemotherapy is controversial. There is concern that antioxidants could reduce the activity of chemotherapy drugs which generate free radicals, such as doxorubicin (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). More evidence is needed to determine what effects, if any, antioxidants such as vitamin C have on chemotherapy.
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Acidification of the urine by vitamin C might increase aspirin levels.
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It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase 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), suggesting this interaction is not clinically significant.
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Acidification of the urine by vitamin C might increase choline magnesium trisalicylate levels.
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It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels (3046,4531). 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), suggesting this interaction probably is not clinically significant.
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Vitamin C might increase blood levels of estrogens.
Details
Increases in plasma estrogen levels of up to 55% occur 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. Increases in plasma estrogen levels may occur when patients who are deficient in vitamin C take supplements (11161). Monitor these patients for estrogen-related side effects.
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Theoretically, vitamin C might decrease levels of fluphenazine.
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In one patient there was a clinically significant decrease in fluphenazine levels when vitamin C (500 mg twice daily) was started (11017). The mechanism is not known, and there is no further data to confirm this interaction.
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Vitamin C can modestly reduce indinavir levels.
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One pharmacokinetic study shows that taking vitamin C 1 gram orally once daily along with indinavir 800 mg orally three times daily reduces the area under the concentration-time curve of indinavir by 14%. The mechanism of this interaction is unknown, but it is unlikely to be clinically significant in most patients. The effect of higher doses of vitamin C on indinavir levels is unknown (11300,93578).
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Vitamin C can increase levothyroxine absorption.
Details
Two clinical studies in adults with poorly controlled hypothyroidism show that swallowing levothyroxine with a glass of water containing vitamin C 500-1000 mg in solution reduces thyroid stimulating hormone (TSH) levels and increases thyroxine (T4) levels when compared with taking levothyroxine alone. This suggests that vitamin C increases the oral absorption of levothyroxine, possibly due to a reduction in pH (102978).
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Vitamin C might decrease the beneficial effects of niacin on high-density lipoprotein (HDL) cholesterol levels.
Details
A combination of niacin and simvastatin (Zocor) effectively raises HDL cholesterol levels in patients with coronary disease and low HDL levels. Clinical research shows that taking a combination of antioxidants (vitamin C, vitamin E, beta-carotene, and selenium) along with niacin and simvastatin (Zocor) attenuates this rise in HDL, specifically the HDL-2 and apolipoprotein A1 fractions, by more than 50% in patients with coronary disease (7388,11537). It is not known whether this adverse effect is due to a single antioxidant such as vitamin C, or to the combination. It also is not known whether it will occur in other patient populations.
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Acidification of the urine by vitamin C might increase salsalate levels.
Details
It has been suggested that acidification of the urine by vitamin C could increase reabsorption of salicylates by the renal tubules, and increase plasma salicylate levels (3046). However, short-term use of up to 6 grams/day vitamin C does not seem to affect urinary pH or salicylate excretion (10588,10589), suggesting this interaction probably is not clinically significant.
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High-dose vitamin C might reduce the levels and effectiveness of warfarin.
Details
Vitamin C in high doses may cause diarrhea and possibly reduce warfarin absorption (11566). There are reports of two people who took up to 16 grams daily of vitamin C and had a reduction in prothrombin time (9804,9806). Lower doses of 5-10 grams daily can also reduce warfarin absorption. In many cases, this does not seem to be clinically significant (9805,9806,11566,11567). However, a case of warfarin resistance has been reported for a patient who took vitamin C 500 mg twice daily. Cessation of vitamin C supplementation resulted in a rapid increase in international normalized ratio (INR) (90942). Tell patients taking warfarin to avoid taking vitamin C in excessively high doses (greater than 10 grams daily). Lower doses may be safe, but the anticoagulation activity of warfarin should be monitored. Patients who are stabilized on warfarin while taking vitamin C should avoid adjusting vitamin C dosage to prevent the possibility of warfarin resistance.
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Below is general information about the adverse effects of the known ingredients contained in the product Vitamin C Complex. Some ingredients may not be listed. This information does NOT represent a recommendation for or a test of this specific product as a whole.
General
...Orally, bilberry fruit, juice, and extracts seem to be well tolerated.
Most Common Adverse Effects:
Orally: Dark-colored stools, flatulence, and gastrointestinal discomfort.
Gastrointestinal
...In one small clinical trial, mild-to-moderate flatulence was reported in 33% of patients taking sieved bilberries and concentrated bilberry juice (91506).
However, the patients in this study had ulcerative colitis, and the study lacked a control group, limiting the validity of this finding. In another small clinical study of males with age-related cognitive impairment, temporary adverse gastrointestinal (GI) effects were reported in 13% of patients drinking a combination of bilberry and grape juice. However, the adverse GI effect rate was identical in patients drinking a placebo juice (110641). A post-marketing surveillance report of 2295 patients using bilberry extract (Tegens) found that 1% of patients complained of GI discomfort and less than 1% experienced nausea or heartburn (35500).
Theoretically, fresh bilberry fruit may have laxative effects. One clinical trial noted an increased frequency of bowel movements following the administration of a combination formulation containing aerial agrimony parts, cinnamon quills, powdered bilberry fruit, and slippery elm bark (35462). It is unclear if these effects were due to bilberry, other ingredients, or the combination.
Other ...Orally, bilberry may cause discoloration of feces and the tongue. In one study, a dark-bluish to black discoloration of both the feces and the tongue was observed following consumption of sieved bilberries and concentrated bilberry juice. In one patient, a slight discoloration of the teeth has also been observed (91506). In another study, 50% of patients reported dark green stools after taking bilberry extract 700 mg twice daily for 4 weeks (104194).
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).
General ...Orally and intravenously, quercetin seems to be well tolerated in appropriate doses. Topically, no adverse effects have been reported. However, a thorough evaluation of safety outcomes has not been conducted.
Gastrointestinal ...Intravenous administration of quercetin is associated with nausea and vomiting (9564).
Neurologic/CNS ...Orally, quercetin may cause headache and tingling of the extremities (481,111500). Intravenously, quercetin may cause pain at the injection site. Injection pain can be minimized by premedicating patients with 10 mg of morphine and administering amounts greater than 945 mg/m2 over 5 minutes (9564). In addition, intravenous administration of quercetin is associated with flushing and sweating (9564).
Pulmonary/Respiratory ...Intravenous administration of quercetin at doses as high as 2000 mg/m2 is associated with dyspnea that may persist for up to 5 minutes (9564).
Renal ...Intravenously, nephrotoxicity has been reported with quercetin in amounts greater than 945 mg/m2 (9563,9564,70304).
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).
General
...Orally, intravenously, and topically, vitamin C is well-tolerated.
Most Common Adverse Effects:
Orally: Abdominal cramps, esophagitis, heartburn, headache, osmotic diarrhea, nausea, vomiting. Kidney stones have been reported in those prone to kidney stones. Adverse effects are more likely to occur at doses above the tolerable upper intake level of 2 grams daily.
Topically: Irritation and tingling.
Serious Adverse Effects (Rare):
Orally: There have been rare case reports of carotid inner wall thickening after large doses of vitamin C.
Intravenously: There have been case reports of hyperoxalosis and oxalate nephropathy following high-dose infusions of vitamin C.
Cardiovascular
...Evidence from population research has found that high doses of supplemental vitamin C might not be safe for some people.
In postmenopausal adults with diabetes, supplemental vitamin C intake in doses greater than 300 mg per day is associated with increased risk of cardiovascular mortality. However, dietary intake of vitamin C is not associated with this risk. Also, vitamin C intake is not associated with an increased risk of cardiovascular mortality in patients without diabetes (12498).
Oral supplementation with vitamin C has also been associated with an increased rate of carotid inner wall thickening in men. There is preliminary evidence that supplemental intake of vitamin C 500 mg daily for 18 months can cause a 2.5-fold increased rate of carotid inner wall thickening in non-smoking men and a 5-fold increased rate in men who smoked. The men in this study were 40-60 years old (1355). This effect was not associated with vitamin C from dietary sources (1355).
There is also some concern that vitamin C may increase the risk of hypertension in some patients. A meta-analysis of clinical research suggests that, in pregnant patients at risk of pre-eclampsia, oral intake of vitamin C along with vitamin E increases the risk of gestational hypertension (83450). Other clinical research shows that oral intake of vitamin C along with grape seed polyphenols can increase both systolic and diastolic blood pressure in hypertensive patients (13162).
Dental ...Orally, vitamin C, particularly chewable tablets, has been associated with dental erosion (83484).
Dermatologic ...Topically, vitamin C might cause tingling or irritation at the site of application (6166). A liquid containing vitamin C 20%, red raspberry leaf cell culture extract 0.0005%, and vitamin E 1% (Antioxidant and Collagen Booster Serum, Max Biocare Pty Ltd.) has been reported to cause mild tingling and skin tightness (102355). It is unclear if these effects are due to vitamin C, the other ingredients, or the combination.
Gastrointestinal ...Orally, the adverse effects of vitamin C are dose-related and include nausea, vomiting, esophagitis, heartburn, abdominal cramps, gastrointestinal obstruction, and diarrhea. Doses greater than the tolerable upper intake level (UL) of 2000 mg per day can increase the risk of adverse effects such as osmotic diarrhea and severe gastrointestinal upset (3042,4844,96707,104450). Mineral forms of vitamin C, such as calcium ascorbate (Ester-C), seem to cause fewer gastrointestinal adverse effects than regular vitamin C (83358). In a case report, high dose intravenous vitamin C was associated with increased thirst (96709).
Genitourinary ...Orally, vitamin C may cause precipitation of urate, oxalate, or cysteine stones or drugs in the urinary tract (10356). Hyperoxaluria, hyperuricosuria, hematuria, and crystalluria have occurred in people taking 1 gram or more per day (3042,90943). Supplemental vitamin C over 250 mg daily has been associated with higher risk for kidney stones in males. There was no clear association found in females, but the analysis might not have been adequately powered to evaluate this outcome (104029). In people with a history of oxalate kidney stones, supplemental vitamin C 1 gram per day appears to increase kidney stone risk by 40% (12653). A case of hematuria, high urine oxalate excretion, and the presence of a ureteral stone has been reported for a 9-year-old male who had taken about 3 grams of vitamin C daily since 3 years of age. The condition resolved with cessation of vitamin C intake (90936).
Hematologic ...Prolonged use of large amounts of vitamin C can result in increased metabolism of vitamin C; subsequent reduction in vitamin C intake may precipitate the development of scurvy (15). In one case, a patient with septic shock and a large intraperitoneal hematoma developed moderate hemolysis and increased methemoglobin 12 hours after a high-dose vitamin C infusion. The patient received a blood transfusion and the hemolysis resolved spontaneously over 48 hours (112479).
Neurologic/CNS ...Orally, the adverse effects of vitamin C are dose-related and include fatigue, headache, insomnia, and sleepiness (3042,4844,83475,83476).
Renal ...Hyperoxalosis and oxalate nephropathy have been reported following high-dose infusions of vitamin C. Hyperoxalosis and acute kidney failure contributed to the death of a 76-year-old patient with metastatic adenocarcinoma of the lung who received 10 courses of intravenous infusions containing vitamins, including vitamin C and other supplements over a period of 1 month. Dosages of vitamin C were not specified but were presumed to be high-dose (106618). In another case, a 34-year-old patient with a history of kidney transplant and cerebral palsy was found unresponsive during outpatient treatment for a respiratory tract infection. The patient was intubated for acute hypoxemic respiratory failure, initiated on vasopressors, hydrocortisone, and antibacterial therapy, and received 16 doses of vitamin C 1.5 grams. Serum creatinine level peaked at greater than 3 times baseline and the patient required hemodialysis for oliguria and uncontrolled acidosis. Kidney biopsy revealed oxalate nephropathy with concomitant drug-induced interstitial nephritis (106625). In another case, a 41-year-old patient with a history of kidney transplant presented with fever, nausea, and decreased urine output 4 days after receiving intravenous vitamin C 7 grams for urothelial carcinoma. Serum creatinine levels increased from 1.7 mg/dL to 7.3 mg/dL over those 4 days, and hemodialysis was initiated 3 days after admission due to anuria. Renal biopsy confirmed the diagnosis of acute oxalate nephropathy (109962).
Other ...Intravenously, hypernatremia and falsely elevated ketone levels is reported in a patient with septic shock and chronic kidney disease after a high-dose vitamin C infusion. The hypernatremia resolved over 24 hours after cessation of the infusion (112479).
