A Clinical Trial to Determine the Preventive Effective Dose of Promethazine on Postoperative Nausea and Vomiting after Laparoscopic Gastric Plication

Background: Laparoscopic gastric plication (LGP) is a technique in the restrictive category of bariatric procedures that reduces the gastric volume. Nausea and vomiting are the most common complications after this procedure. The goal of this research is to determine the preventive effective dose of promethazine on postoperative nausea and vomiting (PONV) after laparascopic gastric placation. Methods: After induction of general anesthesia the patients were divided into two groups, the promethazine 50mg group, which was given promethazine 50mg IM plus dexamethasone 8mg IV and the promethazine 25mg group, which was given promethazine 25mg IM plus dexamethasone 4mg IV. The primary endpoints were the incidence and intensity of nausea and vomiting, and severity of abdominal pain score in postoperative periods. Results: Sixty-four morbid obese patients were enrolled into the study. Promethazine50mg group was found to significantly reduce the incidence of PONV in the first 12hrs compared with the other group, (21.87% vs37.5%, P=0/068). At the same time the intensity of PONV in base of numeric rating scale was lower in promethazine 50mg group compared to another group (2.63±0.85 vs4.65± 1.23, P=0/089). The mean severity of abdominal pain was higher in promethazine 25mg group, thus these patients needed more analgesia in comparison with another group. Conclusion: In morbidly obese patients undergoing laparoscopic gastric plication, prophylactive administration of dexamethasone8mg and promethazine 50mg was more effective in the first 12 hours after surgery in reducing the incidence of PONV, and severity of abdominal pain.