Heparin Therapy: regimens and management.

Heparin remains the most effective antithrombotic drug. It acts by combining with plasma antithrombin, thereby accelerating the neurtalisation of thrombin and other acitvated coagulation factors. Full-dose intravenous heparin is indicated in all cases of pulmonary embolism and established deep venous thrombosis, unless there exist compelling contraindications. Continuous intravenous infusion of heparin appears to be safer than intermittent injection. Low-dose subcutaneous heparin is effective in preventing the initial occurrence of thigh vein thrombi and in reducing the incidence of fatal pulmonary embolism in general surgical patients over the age of 40. The efficacy of low-dose heparin in preventing pulmonary emboli following hip surgery has not been established. The incidence of severe heparin-induced thrombocytopenia appears to be rising. Platelet counts should be performed in all patients receiving heparin by any mode of administration.