The preoperative use of cimetidine in reducing acidity of gastric secretion.

Cimetidine, SKF 92334, 1-Cyano 2-methyl -3-2 (Methylimidazole -4- ylmethylthio) ethyl guanidine, C10 H16 N6 S, a competitive antagonist of H2 histamine receptors was given as a single dose orally before induction of anaesthesia in elective and emergency surgery. The volume and pH of the gastric juice were measured in 260 patients of either sex. Cimetidine was given at different times between 0 and 6 hours and was compared with control Group A who received I.M. injection of diazepam 10 mg. and atropine sulphate 0.6 mg, and control Group B who received oral diazepam 10 mg. 1-11/2 hours preoperatively. Cimetidine had maximum effect in reducing the acidity of the gastric secretion when given 2-4 hours preoperatively. Atropine had no substantial effect in reducing the pH and volume of gastric juice when administered with cimetidine.