Ranitidine prophylaxis before anaesthesia in early pregnancy.

Forty patients presenting for vaginal termination of pregnancy, divided randomly into four groups, received either no medication, sodium citrate 30 ml orally, ranitidine 150 mg orally or ranitidine 50 mg intravenously. During the procedure, gastric contents were removed by orogastric tube for volume and pH measurements. Ranitidine, orally and intravenously, significantly increased gastric pH and reduced gastric volume. In the control group only one pH was greater than 2.5. Sodium citrate raised the pH above 2.5 in 6 out of 10 patients. Fasting patients in the first months of pregnancy may be at risk of developing Mendelson's syndrome. Ranitidine is very effective in increasing gastric pH and at the same time reducing gastric volume in such patients.