Current and future antithrombotic agents in children

Thromboembolic complications are increasing in children, and the use of anticoagulation has seen a dramatic increase despite the lack of randomized clinical trials. The most widely used agents in children are heparin and warfarin, however these agents have limitations that are exaggerated in children. This has led to the use of newer agents with improved pharmacologic properties such as low-molecular-weight heparin, however, the use of novel agents such as direct thrombin inhibitors has been limited to case reports. These agents, however, have potential advantages over heparin, low-molecular-weight heparin and warfarin. Current clinical trials are in progress to define the proper dose of two such agents--argatroban (Argatroban, GlaxoSmithKline) and bivalirudin (Angiomax, The Medicines Company). The selective Factor Xa inhibitor fondaparinux (Arixtra, Sanofi-Synthelabo) has not been used in children; however, there are situations in which this agent may be advantageous. This review will discuss the currently available agents, with an emphasis on those that are novel and their potential uses in children.