Prophylactic antiemetics in children undergoing tonsillectomy: high-dose vs low-dose ondansetron

This randomized, double-blind study assessed the impact of two different doses of intraoperative ondansetron on vomiting following tonsillectomy in 240 preadolescent children in a day care surgical setting. After anaesthesia was established by inhalation with N2O/ halothane or intravenously with propofol, the subjects were administered the study drug (50 or 150 micrograms.kg-1 ondansetron, maximum dose 8 mg). Anaesthesia was maintained with N2O/ halothane. The greater dose of ondansetron (150 micrograms.kg-1) had a lower incidence (36% vs 52%) of postoperative vomiting (P = 0.01). In-hospital emesis was not a problem with only 14% of the subjects vomiting. Eight patients sought medical attention for vomiting after discharge from hospital. In-conclusion, 150 micrograms.kg-1 ondansetron is a more effective prophylactic antiemetic than 50 micrograms.kg-1 ondansetron among children undergoing elective tonsillectomy.