OBJECTIVETo study the effects of Ginkgo biloba extract (GBE) on the pharmacokinetics and pharmacodynamics of warfarin and observe the anticoagulant activity of GBE.

METHODA randomized, double-blinded, placebo-controlled, two-way cross-over trial was conducted. Twelve healthy volunteers (sex ratio was 1: 1) were randomized into two groups and received GBE (three pill, tid) or placebo (three pill, tid) for 5 weeks respectively. the subjects received a single dose of warfarin (5 mg) on the day 29. Blood samples for pharmacokinetics and pharmacodynamics assessment were collectd.

RESULTCompared with placebo, BE had no significant pharmacodynamics effects on warfarin and had no effects on prothrombin time (PT) and activated partial thromboplastin time (APTT). GBE extract increased C(max), AUC(0-144 min), AUC(0-infinity), t1/2, of warfarin significantly and decreased CL(F) of warfarin significantly (P < 0.05), and there were no singnificant difference of V(d) (F).

CONCLUSIONGBE has limited effects on the pharmacokinetics but no effects on the pharmacodynamics of single dose warfain in health subjects. GBE has no effects on clotting process alone.