Olanzapine for the prevention of postoperative nausea and vomiting after gynecologic laparoscopic surgery: a randomized controlled trial

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).