The sodium salt form of fondaparinux, a synthetic glucopyranoside with antithrombotic activity. Fondaparinux sodium selectively binds to antithrombin III, thereby potentiating the innate neutralization of activated factor X (Factor Xa) by antithrombin. Neutralization of Factor Xa inhibits its activity and interrupts the blood coagulation cascade, thereby preventing thrombin formation and thrombus development. Check for active clinical trialsusing this agent.