The effect of omeprazole famotidine, ranitidine and placebo in decreasing the risk of aspiration were investigated in 80 pregnant women undergoing elective cesarean operation and their 80 newborns. Group A consisted of pregnant women and divided into four subgroups. Subgroup AI were given omeprazole 40 mg, PO, two hours prior to anaesthetic induction and groups AII, AIII and AIV were given famotidine 40 mg PO, ranitidine 150 mg PO and isotonic saline respectively. Gastric fluids were aspirated through the nasogastric tube before and after induction and at the 30th minute of anaesthesia and volumes and pH values were recorded. Urine samples were taken with the same intervals and pH values were recorded. The volume of gastric fluid and pH were measured in all the newborns (group B) following birth and the values were evaluated according to the subgroups their mother included. Omeprazole, famotidine and ranitidine decreased gastric fluid volume and increased pH significantly when compared to placebo in all the women. Urine pH of the women and gastric fluid volume and pH of the newborns did not show significant differences. All drugs used were concluded to be equally effective in the prophylaxis of aspiration pneumonia
