Fondaparinux for prophylaxis

Numerous therapies to prevent the occurrence of deep vein thrombosis in the orthopaedic population already exist, including antiplatelet agents (namely aspirin), vitamin K antagonists, unfractionated heparin, and the low-molecular-weight heparins (see ACCP Consensus Guidelines) None of these agents are without risk, so orthopedists interested in thrombosis continue to search for newer and better agents. An exciting new class of drug is discussed in this section, the selective factor Xa inhibitor pentasaccharide or fondaparinux. Unfractionated heparin is an indirect thrombin inhibitor whose antithrombotic activity is mediated by interaction with antithrombin (formerly known as antithrombin-3). Pentasaccharide, combined with anti-thrombin, induces conformational changes that greatly enhance antithrombin's ability to inactivate factor Xa. The pros and cons, as well as use in special populations, is discussed in this chapter.