Promethazine Combined with Metoclopramide for the Prevention of Postoperative Nausea and Vomiting in Patients Undergoing Laparoscopic Colorectal Cancer Surgery: A Randomized Controlled Trial.

Purpose: Postoperative nausea and vomiting (PONV) are undesirable postoperative problems in patients undergoing surgery. However, there is currently no satisfactory solution to this problem. Patients and Methods: This prospective, single-center, randomized, double-blind, pilot study was conducted at Gansu Provincial Hospital in China. Patients aged 18-65 years who underwent elective colorectal tumor resection were randomly assigned to receive 6.25 mg promethazine or 1 mL saline intravenously before induction of anesthesia. All patients then received postoperative patient-controlled intravenous analgesia and a continuous metoclopramide infusion at 50 mg. The primary endpoint was the incidence and severity of PONV at 6 h, 24 h, 48 h, and 72 h postoperatively. Results: Between June 2021 and March 2022, 96 eligible patients were included in the final analysis, with 48 patients in the promethazine group and 46 in the saline group. The incidence and severity of nausea during the early period (the first 6 hours postoperatively) were significantly different between groups (P = 0.031 and P = 0.036). A statistically significant difference was found in the incidence and severity within 24 hours postoperatively (P = 0.023 and P = 0.020). The incidence and severity of vomiting were significantly different between groups at 6 h postoperatively (P = 0.043 and P = 0.048). Vomiting incidence and severity were statistically different during the 24 hours postoperatively (P = 0.012 and P = 0.046). A significant statistical difference was found in the satisfaction between the two groups during the postoperative observation period (P = 0.004). Conclusion: Preoperative prophylactic promethazine significantly reduced the incidence and severity of PONV within 24 hours postoperatively, with few adverse effects and no serious adverse reactions. Additionally, patient satisfaction was also improved.