[Haemostasis. A search for an ideal antithrombotics agent].

Heparins and vitamin K antagonist are the main antithrombotic agents used since several years. These two classes of drugs are very effective but not devoid of side effects and require either injections or regular laboratory controls. Therefore new agents have been developed. Two of these agents (fondaparinux and ximelagatran) are already available. Both are of non animal origin, do not induce thrombocytopenia and do not require laboratory controls. In recent studies fondaparinux has shown a better efficacy than low molecular weight heparin in major orthopedic interventions. Ximelagatran, which can be given orally, is now admitted also for short term use. It was hoped that it could replace vitamin K antagonists but increase of liver enzymes occurring after a few weeks is a major problem. Other new drugs are in advanced stage and will be also described.