The cost-effectiveness of newer anticoagulants relative to adjusted-dose warfarin is predicted to be sensitive to the cost of the medications, the risk for cardio- embolism or hemorrhage (cost-effectiveness improving with increasing risk), and the quality of INR control on warfarin. There are many factors to consider in the selection of an anticoagulant for patients with nonvalvular AF. The newer agents offer clearly attractive features such as fixed dose, lack of required blood monitoring, absence of known interaction with the immune complexes associated with heparin-induced and fewer identified drug interactions than warfarin. Most notably, each appears to confer lower risk than adjusted-dose warfarin for ICH, arguably the strongest determinant of long-term safety for anticoagulation (Table 4). These agents also raise important concerns, however, including substantial cost to the healthcare system, renal clearance, short half-lives, general unavailability of a moni- toring test to ensure compliance, and lack of a specific agent to reverse their anticoagulant effects.412 Although a dabigatran dose of 75 mg twice daily was approved for patients with creatinine clearance of 15 to 30 mL/min, such subjects were in fact excluded from RE-LY and have not been extensively studied. 