New oral anticoagulants: will they replace warfarin?

Vitamin K antagonists, such as warfarin, are considered to be the treatment of choice to prevent thromboembolic events, but problems, such as the need for frequent dose adjustment and monitoring of coagulation status, as well as multiple drug and food interactions, make their use difficult for both physician and patient. Two new anticoagulants are now being considered as possible replacements of vitamin K antagonists. Dabigatran, an oral direct thrombin inhibitor has already been approved in the USA for prevention of stroke in patients with atrial fibrillation. Rivaroxaban, a factor Xa inhibitor, and dabigatran are licensed in Europe and Canada for short-term thromboprophylaxis after elective hip or knee replacement surgery. The advantages of these drugs are that they are safe and effective, require no monitoring, have a direct mode of action against only one clotting factor (thrombin or factor Xa), have limited drug interactions, and have rapid peak blood levels. Based on the fact that dabigatran has already been approved for use in the USA, it would appear that it has an advantage over rivaroxaban in becoming the replacement drug for vitamin K antagonists.