If you are currently being treated with any of the following medications, you should not use ginkgo without first talking to your healthcare provider:

Anticonvulsant medications
High doses of Ginkgo biloba could decrease the effectiveness of anticonvulsant therapy in patients taking carbamazepine or valproic acid to control seizures.

Blood-thinning medications
Ginkgo has blood-thinning properties and therefore should not be used if you are taking anticoagulant (blood-thinning) medications, such as aspirin, clopidogrel, dipyridamole, heparin, ticlopidine, or warfarin.

Cylosporine
Ginkgo biloba may be beneficial during treatment with cyclosporine because of its ability to protect cell membranes from damage.

Monoamine oxidase inhibitors (MAOIs)
Ginkgo may enhance the effects (both good and bad) of antidepressant medications known as MAOIs, such as phenelzine and tranylcypromine.

Papaverine
The combination of papaverine and ginkgo may be effective for the treatment of erectile dysfunction in patients who do not respond to papaverine alone.

Thiazide diuretics
Although there has been one literature report of increased blood pressure associated with the use of ginkgo during treatment with thiazide diuretics, this interaction has not been verified by clinical trials. Nevertheless, you should consult with your healthcare provider before using ginkgo if you are taking thiazide diuretics.

Trazodone
Additionally, there has been a report of an adverse interaction between ginkgo and trazodone, an antidepressant medication, that resulted in an elderly patient going into a coma.