Effective dose of granisetron for preventing postoperative emesis in children.

PURPOSE This study was to identify the minimum effective dose of granisetron, a selective 5-hydroxytryptamine type 3 receptor antagonist, to prevent postoperative vomiting in children who have undergone strabismus repair, tonsillectomy or tonsillectomy with adenoidectomy. METHODS In a randomized, double-blind fashion, 80 healthy children aged 4-10 yr were assigned to receive either placebo (saline) or granisetron in a dose of 20, 40 or 80 micrograms.kg-1 iv immediately following the induction of anaesthesia. All subjects received a standardized anaesthetic, which consisted of sevoflurane in nitrous oxide and oxygen. Rescue antiemetics were administered if two or more episodes of vomiting occurred. Postoperative pain was treated with acetaminophene pr or pentazocine iv. During the first 24 hr after anaesthesia, the frequencies of retching and vomiting were recorded in a standardized fashion by nursing staff while subjects were in a hospital. RESULTS There were no differences among four treatment groups with regard to subject characteristics, surgical procedures, anaesthetic and postoperative management or adverse effects. The frequencies of these symptoms were as follows: 65%, 60%, 20% and 15% after administration of placebo, granisetron 20, 40 or 80 micrograms.kg-1. Three children who had received either placebo or granisetron 20 micrograms.kg-1 required another rescue antiemetic drug, whereas none who had received granisetron 40 or 80 micrograms.kg-1 needed rescue drugs. CONCLUSION Granisetron 40 micrograms.kg-1 is an effective antiemetic for preventing retching and vomiting following strabismus repair and tonsillectomy in children. Increasing the dose to 80 micrograms.kg-1 provided no demonstrable benefit in reducing postoperative emesis.