Meeting the unmet needs in anticoagulant therapy.

Although parenteral anticoagulants are suitable for short-term indications, oral anticoagulants are preferable for long-term use. Vitamin K antagonists (VKAs) such as warfarin are the only oral anticoagulants currently licensed for long-term use. Although effective, VKAs have multiple limitations that explain, at least in part, their under-use for stroke prevention in patients with atrial fibrillation (AF) and in other indications. Even when they are prescribed, the level of anticoagulation with VKAs is frequently outside the therapeutic range, potentially compromising safety and efficacy. These limitations have prompted development of new oral anticoagulants that target thrombin or Factor Xa. Designed to be given in fixed doses without routine anticoagulation monitoring, these new agents have the potential to revolutionize long-term anticoagulation therapy.