Interactions with pharmaceuticals: In an Alzheimer's disease patient, ginkgo may have interacted with Trazodone (Desyrel) to cause a coma; reversed by the benzodiazepine antagonist, flumazepril.^28,29 Ginkgo should not be used with any prescription or over-the-counter CNS depressant, including antihistamines. GBE may potentiate monoamine oxidase inhibitors.³⁰ GBE may reduce insulin requirement of diabetics.³ GBE may affect CYP1A2, CYP2D6, and CYP 3A4 to a mild degree, thereby influencing metabolism of multiple drugs.³

Ginkgo does not cause an increase in the INR when given to patients taking warfarin¹¹, but should be used with caution in any patient on anticoagulants or anti-platelet agents, including aspirin, due to its potent inhibition of platelet- activating factor (PAF).³⁰

GBE may lower the threshold for seizures in some patients to due to ginkgotoxin, though this substance is present in minute concentrations in current proparations.³ GBE increases the effectiveness of intracavernosal papaverine injections and may reduce the sexual dysfunction side effects in patients taking antidepressants.³⁰

Interactions with other herbs: Due to its likely GABAergic activity, ginkgo should not be used with any CNS depressant herb such as kava or skullcap.

Ginkgo should be used with caution in conjunction with other herbs known to inhibit platelet aggregation: Bromelain (Ananas comosus), Cayenne (Capiscum frutescens), Chinese skullcap root (Scutellaria baicalensis), Dan shen root (Salvia miltiorrhiza), Garlic (Allium satvium), Ginger (Zingiber officinale), Onion (Allium cepa), Papain leaves (Carica papaya), Reishi fruit bodies (Ganoderma lucidum), Turmeric root (Curcuma longa, C. aromatica).³⁰