Randomized prospective trial of continuous vs intermittent heparin therapy.

Forty-one patients with clinical indications for heparin therapy were randomized to receive continuous intravenous heparin sodium therapy or intermittent (four-hourly bolus) heparin therapy, with control by the activated partial thromboplastin time. Seven of 21 patients receiving intermittent therapy had major bleeding episodes, whereas none of the 20 patients receiving continuous heparin therapy had major bleeding (P = .005). One patient on continuous therapy had a pulmonary embolus, while none on intermittent therapy had recurrent thromboembolism. Two heavily bleeding patients on intermittent therapy were switched to continuous treatment after bleeding was controlled. The use of continuous heparin therapy appears significantly safer with regard to hemorrhagic complications than the use of intermittent therapy.