Medical illness and hospitalization increase the risk of developing venous thromboembolism, which, along with associated complications, leads to poorer patient outcomes and an increased healthcare burden. Thromboprophylaxis significantly reduces the risk of venous thromboembolism in acutely ill medical patients, and current guidelines recommend that unfractionated heparin, low molecular weight heparin or fondaparinux should be administered for the duration of hospitalization or immobilization. Other guidelines advise thromboprophylaxis with these agents for up to 14 days. Despite this guidance, many patients do not receive adequate thromboprophylaxis. Furthermore, the duration of recommended prophylaxis may not be sufficient to ensure protection while patients are at risk of venous thromboembolic events.