Objective: To study the effects of Ginkgo biloba extract (GBE) on the pharmacokinetics and pharmacodynamics of warfarin and observe the anticoagulant activity of GBE.
Method: A 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.
Result: Compared 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).
Conclusion: GBE 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.