A Specific Antidote for Reversal of Anticoagulation by Direct and Indirect Inhibitors of Coagulation Factor Xa

Although new oral anticoagulants are replacing war-farin for stroke prevention in atrial fibrillation and for the prevention and treatment of venous thromboem-bolism, the lack of antidotes is a concern. Consequently, the development of a potential antidote for oral factor Xa inhibitors, such as rivaroxaban and apixaban, represents a major breakthrough. For decades, vitamin K antagonists (VKAs), such as warfarin, were the only orally available anticoagulants. This situation changed with the recent introduction of oral direct thrombin and factor Xa inhibitors. Designed to be given in fixed doses without laboratory monitoring, the new oral anticoagulants (NOACs) are more convenient to administer than warfarin. When compared with warfarin in large phase III clinical trials, NOACs were at least as effective as warfarin, but were associ-ated with less intracranial bleeding. Despite these advantages