Drug-induced gastrointestinal bleeding. Report from the Boston Collaborative Drug Surveillance Program, Boston University Medical Center.

Rates of drug-induced gastrointestinal bleeding were estimated from data on 16 646 consecutively monitored medical inpatients who had no known predisposing illness. Heparin, warfarin, ethacrynic acid, steroids, and aspirin-containing drugs were associated with gastrointestinal bleeding and were estimated to account for about two-thirds of such bleeds. Major gastrointestinal bleeding, defined as bleeding severe enough to require transfusion, occurred in only 57 patients (0.3%).