Intravenous idarucizumab, an antibody fragment of a human antibody specific for dabigatran, produced rapid reversal of the anticoagulant effect in patients with bleeding or an urgent surgical indication with no apparent toxic effects or rebound hypercoagulable state. A non–vitamin K antagonist oral anticoagulant, dabigatran etexilate (dabigatran) is an oral thrombin inhibitor that is licensed for the prevention of stroke in patients with nonvalvular atrial fibrillation and for the prevention and treatment of venous thromboembolism. Although dabigatran is associated with less serious bleeding than warfarin, 1 – 3 life-threatening bleeding can occur; in addition, dabigatran-treated patients may require urgent surgery or intervention, and dabigatran can increase the risk of perioperative bleeding. To improve the treatment of such patients, a specific dabigatran-reversal agent would be beneficial. Idarucizumab, a monoclonal antibody fragment, binds dabigatran with an affinity that is 350 times as . . .