herb-drug interaction
12 interactions related to herb-drug interaction
aspirin + ginkgo
Ginkgo biloba can inhibit platelet-activating factor (PAF) and platelet aggregation, which may add to aspirin's irreversible inhibition of cyclooxygenase-1 and thromboxane A2. Observational data suggest a modest increase in minor bleeding events when the two are combined, and there are case reports of more serious bleeds in vulnerable patients, though a controlled trial found no measurable added effect on platelet function.
rivaroxaban + ginkgo
Rivaroxaban is a Factor Xa inhibitor and ginkgo has mild antiplatelet activity, so combining them was theorized to add to bleeding risk. However, a controlled trial in healthy subjects found standardized EGb 761 ginkgo extract did not change rivaroxaban's pharmacokinetics, anti-Factor Xa activity, or coagulation parameters, and caused no bleeding-related adverse events.
apixaban + st. john's wort
St. John's wort strongly induces both CYP3A4 (apixaban's main metabolizing enzyme) and P-glycoprotein (its efflux transporter). Taken together, it speeds apixaban's breakdown and clearance, lowering blood levels and weakening clot protection, which raises the risk of stroke or thromboembolism.
glipizide + berberine
Berberine lowers blood sugar on its own and also slows the breakdown of glipizide by inhibiting the liver enzyme CYP2C9. Taken together, the two effects can stack and increase the risk of low blood sugar (hypoglycemia), which with a sulfonylurea like glipizide can be prolonged. Do not combine them without prescriber supervision.
dabigatran + st. john's wort
St. John's wort can modestly induce the P-glycoprotein (P-gp) transporter that dabigatran depends on for absorption. With repeated use this may lower dabigatran blood levels somewhat, in theory reducing clot protection. The measured effect in human studies is weak and there are no reported thrombosis cases from the pairing, but because dabigatran is given for serious clotting conditions and the herb's effect lingers after stopping, the combination is best avoided.
warfarin + ginkgo
Warfarin and ginkgo act on clotting through different pathways, raising a plausible but not firmly proven bleeding concern.
clopidogrel + ginkgo
Clopidogrel blocks the platelet P2Y12 ADP receptor, while ginkgo biloba inhibits platelet-activating factor through a separate pathway. A controlled healthy-volunteer study found no measurable added platelet inhibition, but case reports and an observational analysis link the combination to bleeding. The realistic concern is a modest, additive bleeding risk, most relevant in older patients and those also taking aspirin.
glipizide + bitter melon
Bitter melon (Momordica charantia) has its own blood-sugar-lowering activity through several mechanisms, including enhanced glucose uptake into muscle and possible effects on insulin secretion. Combined with the sulfonylurea glipizide, the effects can add together and push blood sugar too low, with the greatest risk after meals and in higher-risk patients.
furosemide + licorice
Glycyrrhizin in licorice inhibits 11-beta-hydroxysteroid dehydrogenase type 2, allowing cortisol to act on mineralocorticoid receptors and driving renal potassium loss. Combined with furosemide, which already wastes potassium, this can add up to a markedly higher risk of significant hypokalemia, worsening edema, raised blood pressure, and arrhythmia.
glipizide + ginseng
Ginseng — especially American ginseng (Panax quinquefolius) — can lower blood sugar after meals, and glipizide also lowers blood sugar by stimulating insulin release. Taken together, their glucose-lowering effects can add up, modestly increasing the risk of hypoglycemia. Let the prescriber who manages your glipizide know before starting any ginseng product.
clopidogrel + garlic
Clopidogrel blocks the platelet P2Y12 ADP receptor to prevent clots. Concentrated garlic supplements also have a mild antiplatelet effect through sulfur compounds such as allicin and ajoene. Taken together, the antiplatelet effects can add up and may modestly raise bleeding risk, especially before procedures. Culinary garlic in food amounts is not a meaningful concern.
spironolactone + licorice
Glycyrrhizin in licorice is converted to glycyrrhetinic acid, which inhibits the kidney enzyme 11-beta-hydroxysteroid dehydrogenase type 2. This lets cortisol stimulate the mineralocorticoid receptor - the same receptor spironolactone is designed to block. The two pull in opposite directions: licorice tends to raise blood pressure and lower potassium, while spironolactone lowers blood pressure and raises potassium, so the herb can partially blunt the drug's intended effect.