Low-molecular-weight heparins: weeks or months instead of days of treatment.

Low-molecular-weight heparins (LMWHs) have been used for more than a decade in the prophylaxis and treatment of venous thromboembolism and recently in coronary artery disease. During the past few years, the duration of treatment has been increased in several pathologic conditions. A number of clinical studies provided evidence that the duration of prophylaxis after hip replacement should be prolonged up to 35 days after surgery. Several clinical trials concluded that LMWHs provide an effective and safe alternative to oral anticoagulants in the secondary prevention of deep vein thrombosis. A recent trial showed that extended dalteparin treatment is useful for protection against further complications while patients are waiting for invasive procedures. Finally, LMWHs seem to be safe during pregnancy.