Prophylaxis for vomiting by children after tonsillectomy: ondansetron compared with perphenazine.

We have compared the effects of ondansetron and perphenazine on vomiting after tonsillectomy in 216 healthy children, aged 2-12 yr. The study was randomized, stratified, blocked and double blind. Anaesthesia was induced with propofol i.v. or by inhalation of halothane and nitrous oxide. Ondansetron 150 micrograms kg-1 or perphenazine 70 micrograms kg-1 was administered i.v. after induction of anaesthesia in a double-blind manner. Perioperative management of emesis, pain, fluids and patients discharge were standardized. Ondansetron and perphenazine had similar effects on postoperative vomiting (44% vs 41%; ondansetron vs perphenazine P = 0.77). By logistic regression analysis, the only significant predictor of postoperative vomiting was sex, that is males had a greater incidence of vomiting (49% vs 35%; P = 0.016). In-hospital vomiting was associated with a prolongation of stay in the day-care surgical unit of 7 min per episode of vomiting (P = 0.015). We conclude that ondansetron and perphenazine had similar effects on vomiting in children after tonsillectomy in a day-case setting.