Acetaminophen and Other Risk Factors for Excessive Warfarin Anticoagulation

Abstract
WARFARIN is highly effective in preventing thromboembolism in a variety of conditions.1 Its major complication is hemorrhage, which can cause severe morbidity and death. In addition, fear of major hemorrhage frequently dissuades patients and physicians from use of anticoagulants in conditions for which such agents are beneficial. Major hemorrhage in patients receiving warfarin is strongly associated with the intensity of anticoagulation.2-5 In particular, the risk of intracranial hemorrhage, the most feared complication of anticoagulation, increases dramatically at international normalized ratio (INR) levels greater than 4.0.6,7