Cimetidine premedication in elective caesarean section.

A single intramuscular injection of Cimetidine was compared to oral antacid premedication in 17 patients undergoing elective Caesarean section. Seven patients in the Cimetidine group and four in the antacid group had gastric volumes in excess of 50 ml after induction of anaesthesia, while two patients in each group had gastric pH less than 2.5 after induction. Cimetidine was as effective as antacid in raising gastric pH but neither was completely reliable. This study reconfirms the high gastric volumes in pregnant patients with the need for preventative measures against aspiration during the induction of anaesthesia.