Unwitting heparin abuse in a drug addict

There have been frequent reports on oral anticoagulant abuse. Less common is the surreptitious use of heparin by patients. We report here a case of unwitting heparin abuse. We presume that the heroin the patient was using was being cut with heparin. This supposition is supported by the partial thromboplastin time returning to normal on all subsequent tests; the heparin half-life is only about 4 hours. We feel that heparin or heparin-like substances should be considered as a cause for prolonged partial thromboplastin times in patients who are intravenous drug abusers.