Warfarin replacements: Mechanisms underlying emerging agents

Warfarin is effective for the prevention and treatment of thromboembolic disorders. However, warfarin has a narrow therapeutic window, unpredictable pharmacology, and food and drug interactions that require regular monitoring and dose adjustment. Therefore, there is a clear need for new anticoagulants that can overcome these limitations. There are a number of potential targets for new anticoagulants within the coagulation cascade; factor Xa and thrombin are particularly attractive options. There are numerous drugs in development that directly target either factor Xa or thrombin, and have predictable pharmacology, meaning monitoring is unlikely to be required. Dabigatran, apixaban and rivaroxaban are in advanced development for a number of indications including prevention and treatment of venous thromboembolism and prevention of stroke in patients with atrial fibrillation. In the near future, these drugs may be able to offer an alternative to warfarin, providing patients with convenient and effective anticoagulation.