Some Possible Dietary Supplement–Medication Interactions

Some Possible Dietary Supplement–Medication Interactions

Dietary Supplement

Affected Medications

Selected Interaction(s)

Ashwagandha

Thyroid hormones

May increase thyroid hormone levels

Antihyperglycemics

May decrease blood glucose to unsafe levels

Antihypertensives

May augment antihypertensive and blood pressure–lowering effects

Immunosuppressants (eg, cyclosporine, mycophenolate, tacrolimus, prednisone, corticosteroids)Immunosuppressants (eg, cyclosporine, mycophenolate, tacrolimus, prednisone, corticosteroids)

May interfere with medications that suppress immune function

Sedatives

May lead to excessive sedation

Astragalus

Immunosuppressants (eg, cyclosporine, mycophenolate, tacrolimus) Immunosuppressants (eg, cyclosporine, mycophenolate, tacrolimus)

May stimulate the immune system and thereby decrease the effectiveness of medications 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

Bacopa

Anticholinergics or medications that can increase acetylcholine (eg, glaucoma or Alzheimer disease medications)

May decrease the effect of anticholinergic medications or increase the adverse effects of cholinergic medications.

Thyroid hormones

May increase thyroid hormone levels

Medications metabolized by the cytochrome P450 system (eg, warfarin, calcium channel blockers, antiseizure medications)Medications 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

Cannabidiol (CBD)

Sedatives and antidepressants (eg, benzodiazepines, phenobarbital, morphine, alcohol, SSRIs, tricyclic antidepressants)Sedatives and antidepressants (eg, benzodiazepines, phenobarbital, morphine, alcohol, SSRIs, tricyclic antidepressants)

May increase the effect of these medications and cause excessive sedation

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

WarfarinWarfarin

May increase warfarin levels and thus possibly result in bleedingMay increase warfarin levels and thus possibly result in bleeding

Chamomile

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

Medications 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 medications

CyclosporineCyclosporine

May increase cyclosporine serum concentrationsMay increase cyclosporine serum concentrations

Chromium

Insulin, sulfonylureas

May lower blood glucose

Thyroid replacement therapy

May decrease levothyroxine serum levels May decrease levothyroxine serum levels

Coenzyme Q10

WarfarinWarfarin

May decrease response to warfarinMay decrease response to warfarin

Antihypertensives

May augment antihypertensive and blood pressure-lowering effects

Chemotherapy agents

May interfere with the action of chemotherapy medications due to antioxidant effects

Dehydroepiandrosterone (DHEA)

Anticoagulants (eg, warfarin)Anticoagulants (eg, warfarin)

Increases the risk of bleeding

Antidepressants

May trigger mania

Medications with anti-estrogenic effects (eg, tamoxifen, anastrozole, and fulvestrant)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*

Stimulants (eg, caffeine, epinephrine, phenylpropanolamine, pseudoephedrine)Stimulants (eg, caffeine, epinephrine, phenylpropanolamine, pseudoephedrine)

Increases the stimulant effects of other medications, increasing risk of irregular or rapid heartbeat and hypertension

MAOIs

May intensify effects of these medications and increase risk of adverse effects (eg, headache, tremors, irregular or rapid heartbeat, hypertension)

Feverfew

Antimigraine medications (eg, ergotamine—see table Antimigraine medications (eg, ergotamine—see tableSome Characteristics of Headache Disorders by Cause)

May increase heart rate and blood pressure because it has additive vasoconstrictive effects

Antiplatelet medications

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

Garlic

Antihypertensives

May augment antihypertensive and blood pressure-lowering effects

Antiplatelet medications

May increase risk of bleeding by enhancing garlic’s inhibition of platelet aggregation and fibrinolytic effectsMay increase risk of bleeding by enhancing 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)

May increase blood levels of tacrolimus, possibly enough to injure the liverMay increase blood levels of tacrolimus, possibly enough to injure the liver

Ginger

Antiplatelet medications

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

Ginkgo

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 medications 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

Ginseng

Antihyperglycemic medications (eg, glipizide) Antihyperglycemic medications (eg, glipizide)

May intensify effects of these medications, 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

Goldenseal

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

Green tea

AtorvastatinAtorvastatin

NadololNadolol

WarfarinWarfarin

Green tea may decrease the levels and effects of atorvastatin, thus decreasing any lipid-lowering benefitGreen tea may decrease the levels and effects of atorvastatin, thus decreasing any lipid-lowering benefit

Green tea may decrease the levels and effects of nadolol, thus decreasing its blood pressure–lowering effectGreen tea may decrease the levels and effects of nadolol, thus decreasing its blood pressure–lowering effect

May reduce efficacy of warfarin, increasing risk of thromboembolismMay reduce efficacy of warfarin, increasing risk of thromboembolism

Holy Basil

Thyroid hormones

May decrease the efficacy of thyroid hormone drugs

Anticoagulants and antiplatelets

May increase risk of bleeding

Kava

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 medications

May increase hepatotoxicity

Licorice (glycyrriza glabra)

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 medications and increase risk of adverse effects (eg, headache, tremors, manic episodes)

WarfarinWarfarin

May decrease effectiveness of warfarinMay decrease effectiveness of warfarin

Melatonin

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

Milk thistle

Antihyperglycemic medications

May intensify effects of these medications, 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

Reishi

Anticoagulants and antiplatelet medications

May increase the risk of bleeding in patients treated with anticoagulants and antiplatelet medications

Antihypertensives

May produce hypotension in patients on antihypertensive medications

Antihyperglycemic medications

May contribute to additive hypoglycemia in patients on antihyperglycemic medications

Rhodiola

Antidepressants

May cause a rapid heart rate

Anticoagulants (eg, warfarin)Anticoagulants (eg, warfarin)

May increase blood levels causing increased risk of bleeding

Anti-inflammatory medications

Increased blood levels and possibly adverse effects

Immunosuppressants

May decrease effectiveness of immunosuppressants

Antihyperglycemic medications

May decrease blood glucose, triggering hypoglycemia

Antihypertensive medications

May decrease blood pressure further

S-Adenosyl-L-Methionine

Antidepressants

May increase serotonin levels causing serotonin syndrome when given with serotonergic medications, 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

Saw palmetto

Antiplatelets and anticoagulants (eg, warfarinAntiplatelets and anticoagulants (eg, warfarin)

May increase effects and may cause bleeding

Estrogens (eg, oral contraceptives and other products)

May decrease effectiveness of estrogens

St. John’s wort

Benzodiazepines (eg, alprazolam, lorazepam, diazepam)Benzodiazepines (eg, alprazolam, lorazepam, diazepam)

May decrease the effectiveness of benzodiazepines

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

KetamineKetamine

May decrease the effectiveness of ketamineMay decrease the effectiveness of ketamine

Nonnucleoside reverse transcriptase inhibitors (eg, nevirapine, efavirenz)Nonnucleoside reverse transcriptase inhibitors (eg, nevirapine, efavirenz)

Increases metabolism of these medications, reducing their efficacy

Oral contraceptives

Increases metabolism of these medications, reducing their efficacy

Oxycodone, methadone, and tramadolOxycodone, methadone, and tramadol

Decreases serum concentrations and analgesic effects of these medications

PhenobarbitalPhenobarbital

May decrease the effectiveness of phenobarbitalMay decrease the effectiveness of phenobarbital

Photosensitizing medications (eg, amiodarone, naproxen, sulfonamide antibiotics)Photosensitizing medications (eg, amiodarone, naproxen, sulfonamide antibiotics)

May increase sun sensitivity

Protease inhibitors (eg, indinavir, saquinavir)Protease inhibitors (eg, indinavir, saquinavir)

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 medications

Statins (eg, atorvastatin, lovastatin, rosuvastatin) Statins (eg, atorvastatin, lovastatin, rosuvastatin)

May decrease the effectiveness of statins

Tricyclic antidepressants (eg, desipramine, amitriptyline)Tricyclic antidepressants (eg, desipramine, amitriptyline)

May augment effects of these medications

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

Valerian

Sedatives (eg, barbiturates, benzodiazepines)

May intensify effects of sedatives

Zinc

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

* Sale of supplements containing ephedra is banned in the United States.

† 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.

* Sale of supplements containing ephedra is banned in the United States.

† 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.