Ginkgo biloba: Significant Interactions


Due to its platelet-activating factor antagonist activity, Ginkgo biloba may theoretically enhance the effects of these drugs and increase risk of bruising or bleeding; however, three clinical trials have cast doubt on the clinical significance of this activity — observe patients taking this combination.


Theoretically, ginkgo may increase bleeding risk when used together with warfarin; however, two randomised double-blind studies have found that Ginkgo biloba does not affect the pharmacokinetics, pharmacodynamics, INR or clinical effects of warfarin, and two clinical trials have not found evidence of significant effects on bleeding. Due to the potential seriousness of such an interaction, caution is still advised.


Cholinergic activity has been identified for ginkgo; therefore, combined use may theoretically increase drug activity — observe patients using this combination, although the effects may be beneficial when used under supervision.


In vivo research suggests that ginkgo can prevent doxorubicin-induced cardiotoxicity suggesting a potentially beneficial interaction, although no human studies are available to confirm clinical significance.


Ginkgo biloba may reduce the sexual dysfunction side-effects of these drugs and improve sleep continuity; however, results from clinical studies are mixed — possible beneficial interaction.


There is a report of two patients using valproatewho experienced seizures with ginkgo use. There is also a report of a patient taking Dilantin and Depakote and ginkgo, together with other herbal medicines, who suffered a fatal breakthrough seizure, with no evidence of non-compliance with anticonvulsant medications. The autopsy report revealed subtherapeutic serum levels for both anticonvulsants Depakote and Dilantin; however, it is uncertain whether effects can be attributed to ginkgo — observe patient taking ginkgo with these medicines.


In three clinical trials, the effectiveness of haloperidol was enhanced when co-administered with 360 mg daily of ginkgo — beneficial interaction.


As a herb with significant antioxidant activity, it has also been employed as a means of reducing the nephrotoxic effects of cisplatin, a use supported by one in vivo study — possible beneficial interaction; however, use only under professional supervision.