Comparison of ondansetron and prochlorperazine for the prevention of nausea and vomiting after adenotonsillectomy.

This study has compared the incidences of nausea, vomiting and headache after ondansetron 0.06 mg kg-1 i.v., prochlorperazine 0.2 mg kg-1 i.m. and prochlorperazine 0.1 mg kg-1 i.v. given during induction of general anaesthesia to 282 patients undergoing adenotonsillectomy. The cardiovascular effects of the drugs were similar. After operation, nausea per se and vomiting per se occurred with similar frequency, in between 6% and 11% and 11% and 19%, respectively, in each test group. Nausea and vomiting in the same patient was reduced from 29% to 2% by i.v. ondansetron (P < 0.0005) and to 3% by i.m. prochlorperazine (P < 0.0005), and appeared to be less severe in these groups. Headache was most frequent after i.v. ondansetron (35%: P < 0.05), but occurred with similar frequency after i.m. prochlorperazine (32%) and i.v. prochlorperazine (29%).