INDICATIONS: Direct inhibitors of thrombin, such as hirudin, are directed against the active site and the recognition site of thrombin. Because of their low-molecular-weight, they can inactivate thrombin bound to fibrin. Prevention of thromboembolic complications in patients undergoing primary total hip or knee replacement is now an authorized indication of desirudin in France. The recommended treatment for heparin-induced thrombocytopenia is lepirudin when there is a clinically evident thrombosis and danaparoid sodium, a mixture of anticoagulant glycosaminoglycans in an antithrombotic prophylaxis setting. LMWH: Low-molecular weight heparins are not yet authorized in France for the treatment of pulmonary embolism. However, deep venous thrombosis can be securely treated with one daily fixed dose of nadroparin or tinzaparin. ORAL ANTICOAGULATION: The duration of anticoagulation therapy in patients with venous thromboembolism remains controversial. Three to six months of therapy is recommended after a first episode of venous thromboembolism; the shorter regimen may be chosen when there is an identifiable and transient risk factor, and the longer when the thrombosis is idiopathic. In the context of primary prevention of ischaemic heart disease low intensity oral anticoagulation could be recommended in men at high risk.