Pre-operative ranitidine. Effect of a single intravenous dose on pH and volume of gastric aspirate.

Ninety-four patients undergoing elective surgery received ranitidine 100 mg or 50 mg intravenously one hour pre-operatively, or acted as controls. A gastric aspirate pH in excess of 2.5 one to two hours after administration was achieved in 93% of patients given 100 mg, 88% of those given 50 mg, and 61% of controls. There were no significant differences in the volumes of gastric aspirate.