Current issues in anticoagulation

Anticoagulation therapy with unfractionated heparin, low-molecular-weight heparins and oral vitamin K antagonists is currently the mainstay of treatment and prevention of thromboembolic disorders (such as deep vein thrombosis, pulmonary embolism and stroke prevention in patients with atrial fibrillation). Although these therapies have proven benefits, they also have important limitations that result in their underuse in routine clinical practice. Consequently, many patients identified by guidelines as requiring anticoagulant therapy receive no or inadequate treatment. Heparins require parenteral administration and pose the risk of heparin-induced thrombocytopenia. Vitamin K antagonists have a narrow separation of antithrombotic and haemorrhagic effects and numerous food and drug-drug interactions, and require frequent coagulation monitoring and dose adjustment to ensure effective antithrombotic protection while minimizing the risk of bleeding complications. In response to these limitations, several new anticoagulants have recently been developed, including selective factor Xa inhibitors such as fondaparinux and ximelagatran, the first oral agent in the new class of direct thrombin inhibitors and the first new oral anticoagulant for almost 60 years. Ximelagatran possesses many of the properties of an ideal agent for anticoagulation therapy. With its oral formulation, consistent and predictable pharmacological profile and no coagulation monitoring, ximelagatran has the potential to increase the use and duration of anticoagulation treatment in thromboembolic disorders and to reduce the burden associated with long-term management.