Updated guidelines on outpatient anticoagulation.

The American College of Chest Physicians provides recommendations for the use of anticoagulant medications for several indications that are important in the primary care setting. Warfarin, a vitamin K antagonist, is recommended for the treatment of venous thromboembolism and for the prevention of stroke in persons with atrial fibrillation, atrial flutter, or valvular heart disease. When warfarin therapy is initiated for venous thromboembolism, it should be given the first day, along with a heparin product or fondaparinux. The heparin product or fondaparinux should be continued for at least five days and until the patient's international normalized ratio is at least 2.0 for two consecutive days. The international normalized ratio goal and duration of treatment with warfarin vary depending on indication and risk. Warfarin therapy should be stopped five days before major surgery and restarted 12 to 24 hours postoperatively. Bridging with low-molecular-weight heparin or other agents is based on balancing the risk of thromboembolism with the risk of bleeding. Increasingly, self-testing is an option for selected patients on warfarin therapy. The ninth edition of the American College of Chest Physicians guidelines, published in 2012, includes a discussion of anticoagulants that have gained approval from the U.S. Food and Drug Administration since publication of the eighth edition in 2008. Dabigatran and apixaban are indicated for the prevention of systemic embolism and stroke in persons with nonvalvular atrial fibrillation. Rivaroxaban is indicated for the prevention of deep venous thrombosis in patients undergoing knee or hip replacement surgery, for treatment of deep venous thrombosis and pulmonary embolism, for reducing the risk of recurrent deep venous thrombosis and pulmonary embolism after initial treatment, and for prevention of systemic embolism in patients with nonvalvular atrial fibrillation.