Ginkgo biloba extract × Warfarin

The European ginkgo monograph notes that concomitant use with anticoagulants increases bleeding risk and that the product should only be taken after consulting a doctor in anticoagulant treatment or bleeding tendency. Ginkgolides inhibit platelet-activating factor, so the effect adds to warfarin at a different step of haemostasis.

Bruises from minimal knocks, gums bleeding when brushing, repeated nosebleeds. Spontaneous intracranial and ocular haemorrhage have been reported with ginkgo. The INR may stay in range, because the platelet pathway does not show up in that measure.

Avoid the combination unless the prescriber has explicitly indicated it. The monograph also advises stopping ginkgo two weeks before planned surgery. If the patient takes it for memory or tinnitus, it helps to know that efficacy in those indications is disputed, while the bleeding risk added to warfarin is concrete.