[Melatonin, methadone, tacrine, vitamin K antagonists and low-molecular-weight heparin].

Presentation of three controversial drugs with unequal value and of new anticoagulation strategies. The renewal of interest in oral anticoagulants is striking; it is the consequence of the better measure of the hypocoagulability and a diminution of the risk of haemorrhage. Also as striking, is the extension of the preventive and curative indications of the low molecular weight heparins.