Ginkgo Biloba Research Today is a free monthly online journal that collates and summarizes the latest research about Ginkgo Biloba, including details on ginkgo biloba, herbal remedies, side effects, benefits.

Investigation of the effects of herbal medicines on warfarin response in healthy subjects: a population pharmacokinetic-pharmacodynamic modeling approach.

Jiang X, Blair EY, McLachlan AJ

Faculty of Pharmacy, the University of Sydney, NSW 2006, Australia.

Systematic evidence regarding herb-drug interactions is lacking. This study investigated herb-drug interactions with warfarin. S-warfarin concentration and response (prothrombin complex activity) data from healthy subjects (n = 24) who received a single warfarin dose (25 mg) and either St John's wort, Asian ginseng, Ginkgo biloba, or ginger were analyzed using a population pharmacokinetic-pharmacodynamic modeling approach. The ratio of S-warfarin apparent clearance (CL/F) compared to control was 1.39 +/- 0.06 and 1.14 +/- 0.04 after St John's wort and Asian ginseng pretreatment, respectively. Other pharmacokinetic and pharmacodynamic parameters were unaffected. Coadministration of St John's wort significantly increased S-warfarin CL/F, whereas treatment with Asian ginseng produced only a moderate increase in CL/F. Ginkgo and ginger did not affect the pharmacokinetics of warfarin in healthy subjects. None of the herbs studied had a direct effect on warfarin pharmacodynamics. Studies in anticoagulated patients are warranted to assess the clinical significance of these herb-drug interactions.

Published 19 October 2006 in J Clin Pharmacol, 46(11): 1370-8.
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