Drug Interactions with Ginkgo (Gingko biloba)
Ginkgo is intended to stimulate memory[111] and improve circulation. Inhibition of
platelet activating factor receptor leading to hemorrhage is its most common unwanted
effect. The pharmacologically active components are ginkgolides A, B and C, and bilobabides[112]. Case reports have indicated possible risks of spontaneous hemorrhage due
to synergy with several platelet-inhibiting drugs and non-steroidal anti-inflammatory
drugs (NSAIDs). A small study demonstrated that ginkgolides inhibited weal and flare
responses to platelet-activating factor in healthy volunteers, and platelet aggregation in
platelet-rich plasma[113]. A 70-year-old man was reported to suffer from spontaneous hyphema associated with ginkgo extract intake[114]. A 71-year-old man died of a intracerebral hemorrhage while taking ibuprofen for 4 weeks having also taken Gingko biloba
extract for 2 years[115]. In a similar manner, a 78-year-old woman developed apraxia
induced by an intracerebral hemorrhage while taking Gingko bilobain conjunction with
chronic warfarin therapy[116]. In addition to possible interactions associated with hemostasis, a 26-year-old man complained of priapism associated with concurrent use of risperidone and ginkgo [117].
Further evidence of possible drug interactions involvingGingko bilobais supported by
three in vitro studies that have shown inhibition of CYP3A4 and P-gp activity, net digoxin
flux in intestinal epithelial cells[118], intestinal and hepatic glucuronidation of mycophenolic