Following reports of bleeding upon Ginkgo intake, we assessed whether Ginkgo extract EGb 761® affects coagulation or platelet function or increases the risk of bleeding. In a double-blind, placebo-controlled trial, prothrombin time, activated partial thromboplastin time, international normalized ratio and bleeding time were measured in patients with Alzheimer’s dementia at baseline, weeks 6 and 26. A total of 513 patients were randomized to 120 mg (n = 169) or 240 mg EGb 761® (n = 170) or placebo (n = 174). No relevant changes were found for coagulation parameters and bleeding time. Numbers of bleeding-related adverse events were similar in all groups. Concomitant intake of acetylsalicylic acid was documented for 68 patients in the placebo group and 105 in the EGb 761® groups. Within these groups, the means at baseline and week 26 differed by less than 1 unit for prothrombin time and bleeding time and less than 0.1 unit for international normalized ratio. Data on warfarin treatment in nine patients each taking placebo or EGb 761® did not indicate enhancement of warfarin effects by EGb 761®. No evidence was found that EGb 761® affects hemostasis or increases the bleeding risk. No pharmacodynamic interactions with warfarin or acetylsalicylic acid were found.
