10.1177/0897190004271776SMYTHE ET ALCOMPLICA IONS OF ANTICOAGULANT THERAPY Managing Complications of Anticoagulant Therapy

Understanding the frequency, risk factors, and management of anticoagulant-inducedadverse eventswill assist clinicians in optimizing patient outcomes. The most frequent adverse event of all anticoagulants is major bleeding. Risk factors for major bleeding have been identified with the heparin com-pounds, the direct thrombin inhibitors (DTIs), fondaparinux, and warfarin therapy. Understanding these risk factors can help prevent bleeding events. For cases of clinically signifi-cant bleeding, reversal agents exist primarily for heparin and warfarin. Although less common, nonbleeding adverse events of anticoagulant therapy can also be life threatening. The heparin compounds are associated with the develop-ment of heparin-induced thrombocytopenia (HIT) and osteo-porosis. HIT can result in life-threatening thrombosis and is usually managed with a DTI. Nonbleeding adverse events with warfarin therapy include skin reactions and the devel-opment of venous limb gangrene. Appropriate initiation of warfarin therapy may decrease the risk of venous limb gangrene. KEY WORDS: Anticoagulation, heparin, warfarin, INR, aPTT, ACT. IN CONTRAST TO OTHER PHARMACOLOGICagents, anticoagulants have a relatively short list of adverse events. Understanding anticoagulant- in-duced adverse events is necessary for clinicians to maximize desirable patient outcomes and minimize undesirable outcomes. Overall, bleeding is the most common and concerning undesirable adverse effect. Bleeding events in the presence of anticoagulants are usually a result of too large a dose-related response, the presence of risk factors, or a combination of both. Nonbleeding adverse events can include heparin-induced thrombocytopenia (HIT) and osteoporosis with the heparin-related compounds and skin reac-tions with warfarin. The purpose of this article is to re-view the complications associated with the different classes of anticoagulant therapy and to provide a rec-ommended approach to management