Abstract
PURPOSE: This study was designed to investigate the prophylactic effect of oral olanzapine in postoperative nausea and vomiting after gynecologic laparoscopic surgery. METHODS: ASA I-II, aged 18-75 years, planned to undergo gynecologic laparoscopic surgery with general anesthesia in adult female patients. Using the randomized numbers table, the patients were placed in two groups. Oral olanzapine 5 mg or placebo was given 1 h before anesthesia. All patients received standard antiemetic prophylaxis with dexamethasone and granisetron. The primary outcome was nausea and/or vomiting in the 24 h after the postoperative. RESULTS: A total of 250 patients were randomized, and 241 were analyzed. The primary outcome occurred in 10 of 120 patients (8.3%) in the olanzapine group and 23 of 121 patients (19.2%) in the placebo group (p = 0.014). According to Kaplan-Meier analysis, the probabilities of nausea and/or vomiting in the 24 h after the postoperative in the olanzapine group were lower than in the placebo group (log-rank p = 0.014). In a multivariate Cox analysis, the variables of use of olanzapine [hazard ratio (HR): 0.35, 95% confidence interval (CI): 0.16-0.79; p = 0.012] and use of vasoactive drugs (HR: 2.48, 95% CI: 1.07-5.75; p = 0.034) were independently associated with nausea and/or vomiting in the 24 h after the postoperative. CONCLUSION: Our data suggest that olanzapine relative to placebo decreased the risk of nausea and/or vomiting in the 24 h after gynecologic laparoscopic surgery. TRIAL REGISTRATION: The trial was registered prior to patient enrollment at The Chinese Clinical Trial Registry (https://www.chictr.org.cn/showproj.html?proj=166900, link to registry page, Principal investigator: Nanjin Chen, Date of registration: 25 April 2022).