Ginkgo reinforces warfarin action by heterogeneous mechanisms. It should thus not be used in patients on oral anticoagulant and/or antiplatelet therapy.
- Oral anticoagulants and medicinal plants. An emerging interaction -- Argento A, Tiraferri E, Marzaloni M. -- Ann Ital Med Int. 2000 Apr;15(2):139-43.
Ginkgo may increase the risk of bleeding or potentiate the effects of warfarin therapy.
- Am J Health Syst Pharm 2000 Jul 1;57(13):1221-7; quiz 1228-30 --
Potential interactions between alternative therapies and warfarin. -- Heck AM, DeWitt BA, Lukes AL.
Interactions include bleeding when combined with warfarin, raised blood pressure when combined with a thiazide diuretic and coma when combined with trazodone.
- Drugs 2001;61(15):2163-75 -- Interactions between herbal medicines and prescribed drugs: a systematic review. -- Izzo AA, Ernst E.
The standardized extract of Ginkgo biloba has an inhibitory action on blood pressure and it may influence cortisol release in response to some stress stimuli.
- J Physiol Pharmacol 2002 Sep;53(3):337-48 -- Reduction of rise in blood pressure and cortisol release during stress by Ginkgo biloba extract (EGb 761) in healthy volunteers. -- Jezova D, Duncko R, Lassanova M, Kriska M, Moncek F.
Bilobalide treatment resulted in a significant increase in the levels of glutamate, aspartate, gamma-aminobutyric acid (GABA), and glycine in the hippocampus of mice compared with the control. An increased level of glycine after bilobalide treatment was also detected in the striatum. In the cortex, bilobalide increased the GABA level, whereas it decreased the level of aspartate. These changes in the levels of various amino acids may be involved in the broad spectrum of pharmacological activities of the extract of Ginkgo biloba on the central nervous system.
- Cell Mol Biol (Noisy-le-grand) 2002 Sep;48(6):681-4 -- Effects of chronic administration of bilobalide on amino acid levels in mouse brain. -- Sasaki K, Hatta S, Wada K, Itoh M, Yoshimura T, Haga M.
Reports case of a patient in whom Ginkgo biloba extract proved to be the unique cause of spontaneous hyphema. Ginkgo biloba is known for platelet inhibition and is extensively used in the elderly because of its beneficial effects as a vascular protector. The clinical progression of the present case strongly suggests that Ginkgo biloba may cause hemorrhage and hyphema, even in the absence of any other predisposing factor.
- J Fr Ophtalmol 2002 Sep;25(7):731-2 -- Spontaneous hyphema caused by Ginkgo biloba extract -- Schneider C, Bord C, Misse P, Arnaud B, Schmitt-Bernard CF.
Ginkgo and trazodone may cause an adverse interaction.
- Drugs Aging 2002;19(11):879-86 -- Potential Interactions between Herbal Medicines and Conventional Drug Therapies Used by Older Adults Attending a Memory Clinic. -- Dergal JM, Gold JL, Laxer DA, Lee MS, Binns MA, Lanctot KL, Freedman M, Rochon PA.
Ginkgo may exacerbate seizures although the evidence for this is similarly anecdotal and uncertain.
- 2001 Dec;2(6):524-532 -- Herbal Medicines and Epilepsy: The Potential for Benefit and Adverse Effects. -- Spinella M.
The use of ginkgo biloba should be stopped at least three days before any surgery, as it may increase bleeding.
- Murray, M. -- The Pill Book Guide to Natural Medicines: Vitamins, Minerals, Nutritional Supplements, Herbs, and Other Natural Products. -- Bantam, 2002. 671.