Clinical and pharmacological properties of new oral anticoagulants for the prevention of cerebral thromboembolism: Factor Xa and thrombin inhibitors

Vitamin K antagonists, such as warfarin and phenprocoumon, are the first-line oral anticoagulants for primary and secondary prevention of cerebral embolism in patients with atrial fibrillation. Although vitamin K antagonists can significantly decrease the risk of stroke, their use is limited by several important drawbacks, such as a narrow therapeutic window, the risk of intracranial and gastrointestinal bleeding, interactions with a number of drugs and nutrients, and the need for regular laboratory tests for therapy adjustment. Currently, new oral anticoagulants, such as direct thrombin inhibitors (e.g., dabigatran) and direct factor Xa inhibitors (e.g., apixaban, rivaroxaban), are being developed and tested in clinical trials. Dabigatran and rivaroxaban were recently approved for prevention of cerebral embolism in patients with atrial fibrillation. The advantages of dabigatran in comparison to warfarin are a lower rate of major bleedings with dabigatran 110 mg bid, a better efficacy with dabigatran 150 mg bid, no clinically relevant interactions with other drugs and no need for routine coagulation monitoring. The disadvantages are the absence of antidote and the absence of routine laboratory tests for precise measurements of anticoagulant effect of direct thrombin/ factor Xa inhibitors. This review will focus on thrombin and factor Xa inhibitors, which are new and promising oral anticoagulants for the prevention of cerebral embolism. We will discuss their pharmacological and clinical properties and provide the most recent updates on their clinical trials.