VOMITING AFTER ADENOTONSILLECTOMY IN CHILDREN - A COMPARISON OF ONDANSETRON, DIMENHYDRINATE, AND PLACEBO

We compared the effectiveness of ondansetron, dimenhydrinate, and plac ebo for the prevention of postoperative vomiting in children after ade notonsillectomy. In a randomized, placebo-controlled, double-blind stu dy, 74 children, 2-10 yr of age scheduled for adenotonsillectomy as ou tpatients were given a single IV dose of ondansetron (0.1 mg/kg, n = 2 6), dimenhydrinate (0.5 mg/kg, n = 25), or placebo (saline, n = 23) at induction of anesthesia. The incidence of retching and vomiting (POV) and side effects observed 24 h after surgery were recorded. Demograph ic data were similar among the three groups. The 24-h incidence of POV was 42%, 79%, and 82% in the ondansetron, dimenhydrinate, and placebo groups, respectively (ondansetron compared with dimenhydrinate [P < 0 .02] or placebo [P < 0.01]). The study was stopped after two children vomited large volumes of bloody fluid 9 and 22 h after surgery without previous signs of occult bleeding. Both children had received ondanse tron. We conclude that ondansetron is superior to dimenhydrinate or pl acebo for the prevention of POV after adenotonsillectomy in children. Antiemetics may mask the signs of bleeding after adenotonsillectomy. I mplications: TV ondansetron (0.1 mg/kg) is more effective than both di menhydrinate and placebo in preventing vomiting after adenotonsillecto my in healthy children. However, antiemetics may also mask the presenc e of blood in the stomach by preventing vomiting, and this should be a ppreciated when adenotonsillectomy is performed on an outpatient basis .