A Double-Blind Comparison of Cimetidine and Ranitidine as Prophylaxis against Gastric Aspiration Syndrome.

Preoperative cimetidine, ranitidine, or placebo were administered, orally or intravenously to 190 patients in a double-blind study. The volume and pH of gastric aspirate samples, obtained after tracheal intubation and before extubation, were measured. Both cimetidine and ranitidine produced higher mean pH levels and thus fewer patients "at risk" should gastric aspiration occur (pH less than or equal to 2.5) than did placebo. Intravenous …