The newer target-specific oral anticoagulant medications dabigatran, rivaroxaban, apixaban, and edoxaban have become increasingly popular alternatives to the vitamin K antagonist, warfarin (see Warfarin and Superwarfarins), the former mainstay of oral anticoagulation for prevention and treatment of venous thrombus events and stroke risk reduction in atrial fibrillation. These newer drugs inhibit a single target-specific step in coagulation rather than blocking multiple vitamin K–dependent blood factors as done by warfarin.