Ginkgo Interactions

Ginkgo biloba can induce CYP2C19, an enzyme involved in clearing phenytoin, which may lower phenytoin blood levels and raise the risk of breakthrough seizures. A published fatal case report described subtherapeutic phenytoin and valproate levels in a patient who had been self-administering ginkgo. Ginkgo also carries its own seizure-related signal. If you take phenytoin, avoid ginkgo and review any supplement changes with your doctor or pharmacist.

Ibuprofen reduces platelet aggregation through COX-1 inhibition, and Ginkgo biloba has antiplatelet activity through ginkgolide B's antagonism of platelet-activating factor. Used together they can compound the effect on platelets and raise bleeding risk; a fatal intracerebral hemorrhage has been reported in a long-term ginkgo user who started regular ibuprofen.

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.

Warfarin and ginkgo act on clotting through different pathways, raising a plausible but not firmly proven bleeding concern.

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.

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.

Pairing a standardized ginkgo biloba extract with phosphatidylserine appears to improve absorption of ginkgo's active fraction. In one small placebo-controlled crossover trial, the ginkgo-phosphatidylserine complex produced modest improvements in memory performance and speed in healthy young adults, where the same dose of ginkgo alone did not.