Oral ondansetron decreases vomiting after tonsillectomy in children

Vomiting is a common, unpleasant aftermath of tonsillectomy in children. Intraoperative intravenous ondansetron (OND) reduces vomiting after this operation. Our double-blind, placebo-controlled, randomized investigation studied the effect of the oral form of OND on vomiting after outpatient tonsillectomy in children. We studied 233 healthy children age 2-14 yr undergoing elective tonsillectomy. Subjects were given placebo (PLAC) or OND 0.1 mg.kg-1 rounded off to the nearest 2 mg one hr before surgery. Anaesthesia was induced with either propofol or halothane/N2O. Vecuronium 0.1 mg.kg-1 was administered at the discretion of the anaesthetist. Anaesthesia was maintained with halothane/N2O, 50 micrograms.kg-1 midazolam iv and 1-1.5 mg.kg-1 codeine im. At the end of surgery, residual neuromuscular blockade was reversed with neostigmine and atropine. All episodes of in-hospital emesis were recorded by nursing staff. Rescue antiemetics in the hospital were 1 mg.kg-1 dimenhydrinate iv for vomiting x 2 and 50 micrograms.kg-1 droperidol iv for vomiting x 4. Parents kept a diary of emesis after discharge. Postoperative pain was treated with morphine, codeine and/or acetaminophen. The two groups were similar with respect to demographic data, induction technique and anaesthesia time. Oral OND (n = 109) reduced postoperative emesis from 54% to 39%, P < 0.05. This effect was most dramatic in-hospital, where 10% of the OND-patients and 30% of the PLAC-group vomited, P < 0.05. The OND-subjects required fewer rescue antiemetics, 7% vs 17%, P < 0.05. In conclusion, oral ondansetron decreased the incidence of vomiting after outpatient tonsillectomy in children.