[Low molecular weight heparin]

Low-molecular-weight heparins (LMWHs) are obtained by depolymerization from standard heparin and show substantial advantages compared with the parent compound, by virtue of their different pharmacokinetics and lower interaction with platelets, so that they are supplanting heparin in various clinical indications. In the prophylaxis of venous thromboembolism, LMWHs are more efficacious than unfractionated heparin in patients at high thrombotic risk, and equally efficacious in patients at moderate thrombotic risk, with the benefit of once-a-day administration. In the treatment of acute deep venous thrombosis and pulmonary embolism, LMWHs administered subcutaneously in fixed dose per kg of body weight show equivalent efficacy and safety than intravenous heparin in adjusted dose, and allow home treatment in selected cases. In the treatment of deep venous thrombosis after the acute phase, LMWHs are equally effective and safer than oral anticoagulants. In unstable angina and non Q myocardial infarction, nadroparine and enoxaparin plus aspirin have been shown to be more efficacious than unfractionated heparin plus aspirin. In acute ischemic stroke, preliminary results are promising, but the evidence of efficacy must be substantiated by other studies, which are currently in progress.