Prevention of stress-induced upper gastrointestinal bleeding by cimetidine in patients on assisted ventilation.

A double-blind controlled trial was conducted in which the efficacy of cimetidine in a dosage of 20 mg/kg/24 h in preventing upper gastrointestinal hemorrhage was tested in 34 critically ill patients on assisted ventilation. In 28 patients, 14 on cimetidine and 14 on placebo, gastric pH measurements and blood loss measured by 51Cr-labelled erythrocytes could be analyzed. Although cimetidine produced a markedly lower number of days with a gastric pH below 3.5 (17.4% vs. 72.2%) 5 patients on cimetidine bled as against 1 on placebo. These results do not suggest that cimetidine was effective in preventing stress-induced upper gastrointestinal bleeding.