Double-blind,placebo-controlled,dose-ranging study of ramosetron for the prevention of nausea and vomiting after thyroidectomy

BACKGROUND: Patients receiving general anesthesia during thyroidectomy have a high risk for postoperative nausea and vomiting. OBJECTIVE: This prospective, randomized, double-blind, placebo-controlled, dose-ranging study was undertaken to assess the efficacy and safety of ramosetron, a selective 5-hydroxytryptamine type 3-receptor antagonist, in preventing nausea and vomiting after thyroidectomy. METHODS: Standard general anesthetic technique and postoperative analgesia were employed. Patients undergoing thyroidectomy were randomized to receive IV ramosetron 0.15, 0.3, or 0.6 mg or placebo at completion of the procedure. During the first 48 hours after anesthesia, episodes of emesis and adverse events were assessed by nursing staff who were blinded to patients' treatment assignment. RESULTS: Eighty patients (22 men, 58 women; age range, 28-63 years; weight range, 37-91 kg) were enrolled in the study. There were no differences in demographic characteristics between treatment groups. The numbers of patients who were emesis free (no nausea, retching, or vomiting) 0 to 24 hours after anesthesia were 10 of 20 (50%) with ramosetron 0.15 mg, 17 of 20 (85%) with ramosetron 0.3 mg, 18 of 20 (90%) with ramosetron 0.6 mg, and 8 of 20 (40%) with placebo. The corresponding numbers 24 to 48 hours after anesthesia were 11 of 20 (55%), 18 of 20 (90%), 18 of 20 (90%), and 9 of 20 (45%). At both time points, only the values for ramosetron 0.3 and 0.6 mg were statistically significant versus placebo (P < or = 0.001). No clinically serious adverse events were observed in any group. CONCLUSIONS: In this population of patients receiving general anesthesia while undergoing thyroidectomy, ramosetron 0.3 mg was effective in preventing postoperative nausea and vomiting 0 to 48 hours after anesthesia. Increasing the dose to 0.6 mg provided no demonstrable benefit.