A pharmacologic overview of current and emerging anticoagulants.

ABSTRACT For over 50 years, anticoagulant options for the treatmentand prevention of thrombosis have been limited mainly totraditional agents such as unfractionated heparin and oralvitamin K antagonists such as warfarin.These traditionalagents are fraught with limitations that complicate theirclinical use.A variety of novel anticoagulants with improvedpharmacologic and clinical profiles have recently been intro-duced or are in development, offering benefits over tradi-tional therapies. Specifically, progress has been made in thedevelopment of low-molecular-weight heparins, factor Xainhibitors, and direct thrombin inhibitors. Because of theirconvenience and ease of use, some of these novel com-pounds are competing with the traditional anticoagulantsand are needed additions to the antithrombotic arsenal. A nticoagulant therapy has historically con-sisted of heparins for the treatment of acutethrombosis and vitamin K antagonists forlong-term or chronic treatment. 1 Thougheffective if appropriately dosed and monitored, thesetraditional agents have shortcomings that stem mainlyfrom their nonspecific mechanisms of action and vari-able pharmacodynamics. This has left a persisting needfor novel anticoagulants that have more specific andtargeted action and are easier to administer and man-age.