Some Possible Dietary Supplement–Drug Interactions*
Dietary Supplement | Affected Drugs | Interaction(s) |
|---|---|---|
Thyroid hormones | May increase thyroid hormone levels | |
Antihyperglycemic drugs | May decrease blood glucose to unsafe levels | |
Antihypertensive drugs | May augment antihypertensive and blood pressure-lowering effects | |
Immunosuppressant drugs (eg, cyclosporine, mycophenolate, tacrolimus, prednisone, corticosteroids)Immunosuppressant drugs (eg, cyclosporine, mycophenolate, tacrolimus, prednisone, corticosteroids) | May interfere with drugs that suppress immune function | |
Sedatives | May lead to excessive sleepiness | |
Immunosuppressants (eg, cyclosporine, mycophenolate, tacrolimus) Immunosuppressants (eg, cyclosporine, mycophenolate, tacrolimus) | May stimulate the immune system and thereby decrease the effectiveness of drugs that suppress the immune system such as those used after organ transplant | |
LithiumLithium | May decrease excretion of lithium which can result in increased blood levels and possible serious adverse effectsMay decrease excretion of lithium which can result in increased blood levels and possible serious adverse effects | |
Anticholinergic drugs or drugs that can increase acetylcholine (eg, glaucoma or Alzheimer disease drugs) | May decrease the effect or anticholinergic drugs or increase the adverse effects of cholinergic drugs. | |
Thyroid hormones | May increase thyroid hormone levels | |
Drugs metabolized by the cytochrome P450 system (eg, warfarin, calcium channel blockers, antiseizure medications)Drugs metabolized by the cytochrome P450 system (eg, warfarin, calcium channel blockers, antiseizure medications) | May increase the risk of bleeding or lower blood pressure with calcium channel blockers or sedation with antiseizure medications | |
Sedatives and antidepressants (eg, benzodiazepines, phenobarbital, morphine, alcohol, SSRIs, tricyclic antidepressants)Sedatives and antidepressants (eg, benzodiazepines, phenobarbital, morphine, alcohol, SSRIs, tricyclic antidepressants) | Can increase the effect of these drugs and make people too drowsy | |
Acetaminophen and valproic acidAcetaminophen and valproic acid | May increase the chance of liver injury | |
Antiseizure medications | May increase effect of these medications and may increase adverse effects | |
Lithium Lithium | May increase lithium toxicityMay increase lithium toxicity | |
Barbiturates and other sedatives | May intensify or prolong effects of sedatives because its volatile oils have additive effects | |
Iron supplements | May reduce iron absorption via tannins in the plant | |
WarfarinWarfarin | May increase risk of bleeding because chamomile contains phytocoumarins, which may have additive effects | |
Drugs with estrogenic effects (eg, tamoxifen, hormone replacement therapy, oral contraceptives containing estrogens)effects (eg, tamoxifen, hormone replacement therapy, oral contraceptives containing estrogens) | May interfere with the estrogenic effects of these drugs | |
CyclosporineCyclosporine | May increase cyclosporine serum concentrationsMay increase cyclosporine serum concentrations | |
Insulin, sulfonylureas | May lower blood glucose | |
Thyroid replacement therapy | May decrease levothyroxine serum levels May decrease levothyroxine serum levels | |
WarfarinWarfarin | May decrease response to warfarinMay decrease response to warfarin | |
Antihypertensives | May augment antihypertensive and blood pressure-lowering effects | |
Chemotherapy drugs | May interfere with the action of chemotherapy drugs due to antioxidant effects | |
Anticoagulants (eg, warfarin)Anticoagulants (eg, warfarin) | Increases the risk of bleeding | |
Antidepressants | May trigger mania | |
Drugs with anti-estrogenic effects (eg, tamoxifen, anastrozole, and fulvestrant)Drugs with anti-estrogenic effects (eg, tamoxifen, anastrozole, and fulvestrant) | May decrease the anti-estrogenic effects | |
Triazolam (a benzodiazepine).Triazolam (a benzodiazepine). | May increase the sedative effect | |
Bacille Calmette-Guerin (BCG) vaccine (for tuberculosis) | May decrease the effectiveness of the BCG vaccine | |
Ephedra† | Stimulant drugs (eg, caffeine, epinephrine, phenylpropanolamine, pseudoephedrine)Stimulant drugs (eg, caffeine, epinephrine, phenylpropanolamine, pseudoephedrine) | Increases the stimulant effects of other drugs, increasing risk of irregular or rapid heartbeat and hypertension |
MAOIs | May intensify effects of these drugs and increase risk of adverse effects (eg, headache, tremors, irregular or rapid heartbeat, hypertension) | |
Antimigraine drugs (eg, ergotamine—see table Antimigraine drugs (eg, ergotamine—see tableSome Characteristics of Headache Disorders by Cause) | May increase heart rate and blood pressure because it has additive vasoconstrictive effects | |
Antiplatelet drugs | May increase risk of bleeding because feverfew inhibits platelet aggregation (has additive effects) | |
NSAIDs | Increased risk of bleeding, because both feverfew and NSAIDs may potentially cause bleeding | |
WarfarinWarfarin | May increase risk of bleeding because warfarin may have additive effectsMay increase risk of bleeding because warfarin may have additive effects | |
Antihypertensives | May augment antihypertensive and blood pressure-lowering effects | |
Antiplatelet drugs | May increase risk of bleeding because these drugs enhance garlic’s inhibition of platelet aggregation and fibrinolytic effectsMay increase risk of bleeding because these drugs enhance garlic’s inhibition of platelet aggregation and fibrinolytic effects | |
Isonicotinylhydrazide (isoniazid, or INH)Isonicotinylhydrazide (isoniazid, or INH) | May lower levels | |
Protease inhibitors (eg, saquinavir)Protease inhibitors (eg, saquinavir) | Blood level of protease inhibitors reduced by garlicBlood level of protease inhibitors reduced by garlic | |
WarfarinWarfarin | May increase risk of bleeding by augmenting warfarin’s anticoagulant effectsMay increase risk of bleeding by augmenting warfarin’s anticoagulant effects | |
Tacrolimus (oral)Tacrolimus (oral) | Can increase blood levels of tacrolimus, possibly enough to injure the liverCan increase blood levels of tacrolimus, possibly enough to injure the liver | |
Antiplatelet drugs | May increase risk of bleeding by augmenting inhibition of platelet aggregation | |
WarfarinWarfarin | May increase risk of bleeding by augmenting warfarin’s anticoagulant effectsMay increase risk of bleeding by augmenting warfarin’s anticoagulant effects | |
Antiseizure medications (eg, phenytoin) Antiseizure medications (eg, phenytoin) | May reduce efficacy of antiseizure medications because contaminants in ginkgo preparations may reduce antiseizure effectsMay reduce efficacy of antiseizure medications because contaminants in ginkgo preparations may reduce antiseizure effects | |
Antidepressants | May precipitate serotonin syndrome in patients on other antidepressant medications | |
MAOIs (eg, tranylcypromine)MAOIs (eg, tranylcypromine) | May intensify effects of these drugs and increase risk of adverse effects (eg, headache, tremors, manic episodes) | |
NSAIDs | May increase risk of bleeding by augmenting inhibition of antiplatelet aggregation | |
WarfarinWarfarin | May increase risk of bleeding by augmenting warfarin’s anticoagulant effectsMay increase risk of bleeding by augmenting warfarin’s anticoagulant effects | |
Antihyperglycemic drugs (eg, glipizide) Antihyperglycemic drugs (eg, glipizide) | May intensify effects of these drugs, causing hypoglycemia | |
Aspirin and other NSAIDsAspirin and other NSAIDs | May increase risk of bleeding by augmenting inhibition of antiplatelet aggregation | |
Corticosteroids | May intensify adverse effects of corticosteroids because ginseng has anti-inflammatory effectsMay intensify adverse effects of corticosteroids because ginseng has anti-inflammatory effects May have immunostimulant effects and thus may attenuate the immunosuppressive effects of corticosteroids | |
DigoxinDigoxin | May increase digoxin levelsMay increase digoxin levels | |
Estrogens | May intensify adverse effects of estrogen | |
MAOIs | Can cause headache, tremors, and manic episodes | |
Opioids | May reduce the effectiveness of opioids | |
WarfarinWarfarin | May increase risk of bleeding by augmenting warfarin’s anticoagulant effectsMay increase risk of bleeding by augmenting warfarin’s anticoagulant effects | |
Antihypertensives | Berberine content may increase antihypertensive effects | |
Antihyperglycemics | Berberine may increase hypoglycemic effects | |
Warfarin and heparinWarfarin and heparin | May increase effects of warfarin and heparin, increasing risk of bleedingMay increase effects of warfarin and heparin, increasing risk of bleeding | |
WarfarinWarfarin | May reduce efficacy of warfarin, increasing risk of thromboembolismMay reduce efficacy of warfarin, increasing risk of thromboembolism | |
Thyroid hormones | May decrease the efficacy of thyroid hormone drugs | |
Anticoagulants and antiplatelets | May increase risk of bleeding | |
Sedatives (eg, barbiturates, benzodiazepines) | May intensify or prolong the effects of sedatives | |
Antiparkinsonian medications | May antagonize effects of levodopa and worsen Parkinson diseaseMay antagonize effects of levodopa and worsen Parkinson disease May reduce metabolism of ropinirole and thus cause dopamine toxicityMay reduce metabolism of ropinirole and thus cause dopamine toxicity | |
Hepatotoxic drugs | May increase hepatotoxicity | |
Antihypertensives | May increase salt and water retention and increase blood pressure, making antihypertensives less effective | |
Chemotherapeutics | May decrease effects of paclitaxel and cisplatinMay decrease effects of paclitaxel and cisplatin | |
Corticosteroids | May increase adverse effects of corticosteroids | |
DigoxinDigoxin | May decrease levels of potassium, which increases risk of digoxin toxicityMay decrease levels of potassium, which increases risk of digoxin toxicity | |
Diuretics | May intensify the potassium-wasting effects of most diuretics and interfere with the effectiveness of potassium-sparing diuretics (eg, spironolactone)May intensify the potassium-wasting effects of most diuretics and interfere with the effectiveness of potassium-sparing diuretics (eg, spironolactone) | |
MAOIs | May intensify effects of these drugs and increase risk of adverse effects (eg, headache, tremors, manic episodes) | |
WarfarinWarfarin | May decrease effectiveness of warfarinMay decrease effectiveness of warfarin | |
Anticoagulants (such as warfarin)Anticoagulants (such as warfarin) | May increase risk of bleeding | |
Antiseizure medications | May decrease the effectiveness of antiseizure medications | |
Benzodiazepines | May increase sedative effect | |
MethamphetamineMethamphetamine | May increase the adverse effects of methamphetamineMay increase the adverse effects of methamphetamine | |
Antihyperglycemic drugs | May intensify effects of these drugs, causing hypoglycemia | |
Protease inhibitors (eg, indinavir, saquinavir)Protease inhibitors (eg, indinavir, saquinavir) | May interfere with metabolizing enzymes, lowering blood levels of indinavirMay interfere with metabolizing enzymes, lowering blood levels of indinavir | |
SirolimusSirolimus | May decrease sirolimus clearance in renal transplant patients with hepatic impairmentMay decrease sirolimus clearance in renal transplant patients with hepatic impairment | |
WarfarinWarfarin | May increase risk of bleeding by increasing effects | |
Antidepressants | May cause a rapid heart rate | |
Anticoagulants (eg, warfarin)Anticoagulants (eg, warfarin) | May increase blood levels causing increased risk of bleeding | |
Anti-inflammatory drugs | Increased blood levels and possibly adverse effects | |
Immunosuppressants | May decrease effectiveness of immunosuppressants | |
Antihyperglycemic medications | Can decrease blood glucose, triggering hypoglycemia | |
Antihypertensive medications | Can decrease blood pressure further | |
Antidepressants | May increase serotonin levels causing serotonin syndrome when given with serotonergic drugs, manifested by a rapid heart rate, anxiety, gastrointestinal symptoms, severe muscle rigidity, and possible seizures | |
LevodopaLevodopa | May decrease the effectiveness of levodopaMay decrease the effectiveness of levodopa | |
Antiplatelets and anticoagulants (eg, warfarin) Antiplatelets and anticoagulants (eg, warfarin) | May increase effects and may cause bleeding | |
Estrogens (eg, oral contraceptives and other products) | May decrease effectiveness of estrogens | |
Cyclosporine and tacrolimusCyclosporine and tacrolimus | May reduce blood level of cyclosporine, increasing risk of organ transplant rejectionMay reduce blood level of cyclosporine, increasing risk of organ transplant rejection | |
DigoxinDigoxin | May reduce blood level of digoxin, making it less effective, with potentially dangerous resultsMay reduce blood level of digoxin, making it less effective, with potentially dangerous results | |
Iron supplements | May reduce iron absorption | |
MAOIs | May augment effects of MAOIs, possibly causing very high blood pressure requiring emergency treatment | |
Nonnucleoside reverse transcriptase inhibitors | Increases metabolism of these drugs, reducing their efficacy | |
Oral contraceptives | Increases metabolism of these drugs, reducing their efficacy | |
Oxycodone, methadone, and tramadolOxycodone, methadone, and tramadol | Decreases serum concentrations and analgesic effects of these drugs | |
Photosensitizing drugs (eg, lansoprazole, omeprazole, piroxicam, sulfonamide antibiotics)Photosensitizing drugs (eg, lansoprazole, omeprazole, piroxicam, sulfonamide antibiotics) | May increase sun sensitivity | |
Protease inhibitors | May reduce blood level of protease inhibitors, reducing their efficacy | |
SSRIs (eg, fluoxetine, paroxetine, sertraline)SSRIs (eg, fluoxetine, paroxetine, sertraline) | May augment effects of these drugs | |
Tricyclic antidepressants | May augment effects of these drugs | |
Warfarin and other anticoagulants (eg, direct-acting oral anticoagulants)Warfarin and other anticoagulants (eg, direct-acting oral anticoagulants) | May reduce blood level of warfarin and rivaroxaban, increasing risk of thromboembolismMay reduce blood level of warfarin and rivaroxaban, increasing risk of thromboembolism | |
Sedatives (eg, barbiturates, benzodiazepines) | May intensify effects of sedatives | |
Antibiotics (eg, cephalexin, tetracyclines, quinolones) Antibiotics (eg, cephalexin, tetracyclines, quinolones) | May decrease absorption and effect of the antibiotics when taken within hours of zinc | |
Cisplatin, penicillamine, and chelate integrase inhibitors (eg, dolutegravir)Cisplatin, penicillamine, and chelate integrase inhibitors (eg, dolutegravir) | May be inhibited or inactivated | |
* Caution is required when dietary supplements are used because these products are not standardized and thus vary considerably and because information about their use is continually changing. The theoretical status of many published interactions does not obviate the need for cautious use. Before prescribing any drug, health care practitioners should ask patients whether they are taking dietary supplements and, if so, which ones. Practitioners must identify any potential adverse interactions of drugs and supplements taken by a patient and then determine appropriate drugs and dosages. | ||
† Sale of supplements containing ephedra is banned in the US. | ||
‡ This substance is true, natural licorice, not the more common, artificially flavored licorice candy. | ||
MAOIs = monoamine oxidase inhibitors; NSAIDs = nonsteroidal anti-inflammatory drugs; SSRIs = selective serotonin reuptake inhibitors. | ||