Comparison of ramosetron and ondansetron for the treatment of established postoperative nausea and vomiting after laparoscopic surgery: a prospective, randomized, double-blinded multicenter trial

Background: Postoperative nausea and vomiting (PONV) is a common complication after surgery, which increases physical and psychological discomfort and delays recovery. The aim of this study was to test the hypothesis that ramosetron is comparable to ondansetron for the treatment of established PONV after laparoscopic surgery using a prospective, randomized, double-blinded, noninferiority study. Methods: Patients who had at least two risk factors of PONV and underwent laparoscopic surgery under general anesthesia were assessed for eligibility. Patients who developed PONV within the first 2 h after anesthesia received ondansetron (4 mg) or ramosetron (0.3 mg) intravenously in a randomized double-blind manner. Patients were then observed for 24 h after drug administration. The incidence of nausea and vomiting, severity of nausea, rescue antiemetic necessity, and adverse effects at 0-2 or 2-24 h after drug administration was evaluated. The primary endpoint was the rate of patients exhibiting a complete response, defined as no emesis and no further rescue antiemetic medication for 24 h after drug administration. Results: Among the 583 patients, 210 (36.0%) developed PONV and were randomized to either the ondansetron (n=105) or ramosetron (n=105) group. Patient's characteristics were similar between the groups. The complete response rate was 44.1% in the ondansetron group and 52.9% in the ramosetron group after 24 h of initial antiemetic administration. The incidence of adverse events was not different between the groups. Conclusion: We found evidence to support the noninferiority of ramosetron (0.3 mg) compared to ondansetron (4 mg) for the treatment of established PONV in moderate to high-risk patients undergoing laparoscopic surgery.