Ranitidine and single-dose antacid therapy as prophylaxis against acid aspiration syndrome in obstetric practice.

The efficacy of the non-particulate antacid 0.3 M sodium citrate in single and multiple dose regimes was investigated in 156 obstetric patients, both emergency and elective, who required operative delivery under general anaesthesia. Failure of either of these regimes to elevate the intragastric pH consistently to an acceptable level (greater than 3) led to investigation of a regime combining the histamine H2-receptor antagonist, ranitidine, and a single pre-anaesthetic dose of 0.3 M sodium citrate in a further 170 patients. Satisfactory pH values (greater than 3) were achieved in all patients studied. The results from the first 99 cases were analysed statistically by comparison with the multiple dose sodium citrate regime and showed a very significant improvement in the ranitidine group for intragastric pH and volume. No untoward side-effects were discovered in either mother or baby and the 6-hourly administration of ranitidine, which was easily complied with, had no effect on the progress of labour or operative delivery rate.