Enoxaparin: in the prevention of venous thromboembolism in medical patients.

Enoxaparin (enoxaparin sodium) is a low-molecular-weight heparin that binds to and increases the activity of antithrombin III. The resulting complex inhibits prothrombinase-mediated thrombin generation and direct thrombin generation by binding to factor Xa and thrombin factor IIa. Enoxaparin, used as prophylaxis in medically ill patients at increased risk for thromboembolism, has shown significantly increased efficacy compared with placebo in reducing the incidence of deep vein thrombosis and pulmonary embolism. Indeed, 291 patients receiving subcutaneous enoxaparin 40 mg/day had a frequency of venous thromboembolism of 5.5% during 14 days of treatment, whereas 14.9% of the 288 placebo recipients experienced thromboemboli (p < 0.001). There was no reduction in the incidence of thromboembolism in the 287 recipients of enoxaparin 20 mg/day (15%). In other studies, prophylactic treatment for 7 days with subcutaneous enoxaparin 40 mg/day was at least as effective as unfractionated heparin in reducing the frequency of venous thromboembolism in 959 nonsurgical patients at increased risk for deep vein thrombosis and pulmonary embolism (total incidence = 0.2 and 1.4%, respectively). Moreover, enoxaparin recipients experienced fewer adverse events than did heparin recipients. The most frequent adverse events reported in medically ill and surgical patients receiving enoxaparin 40 mg/day were hemorrhage (17.4 vs 14.3% for placebo), hematoma at injection site, anemia, fever, peripheral edema, nausea, ecchymosis and edema (unspecified site).