Efficacious alternatives to warfarin for patients with nonvalvular atrial fibrillation include the following new anticoagulants: Dabigatran (a direct thrombin inhibitor) 150 mg 2 times a day in patients without severe renal failure (creatinine clearance < 15 mL / minute) and / or liver failure (elevated INR) Apixaban (a direct factor Xa inhibitor) 5 mg 2 times a day in patients ≥ 80 years, in patients with serum creatinine ≥ 1.5 mg / dL and creatinine clearance ≥ 25 mL / minute, or as an alternative to aspirin in patients who cannot take warfarin Rivaroxaban (a direct factor Xa inhibitor) 20 mg once a day for patients without severe renal failure (creatinine clearance < 15 mL / minute) The main advantage of these new anticoagulants is ease of use (eg, no need to check anticoagulation level with a blood test after the initial dose or to use a parenteral anticoagulant such as unfractionated heparin given by continuous infusion when transitioning from parenteral to oral anticoagulants).