A comparison of ondansetron and prochlorperazine for the prevention of nausea and vomiting after tympanoplasty.

PURPOSE: To evaluate the effects on PONV and headache after tympanoplasty of prochlorperazine 0.2 mg.kg-1 i.m., ondansetron 0.06 mg.kg-1 i.v. or placebo (isotonic saline) 0.02 ml.kg-1 i.v. given immediately after induction of anaesthesia prior to tracheal intubation. METHODS: The study was randomised, double blind and prospective. One hundred and forty-eight patients, aged 9-61 yr, received a standardised balanced inhalational anaesthetic with controlled ventilation and induced hypotension. Postoperatively, the frequencies of retching and vomiting in the PACU and of nausea, retching, vomiting, headache, analgesic and antiemetic requirements in the surgical ward for 24 hr were recorded. RESULTS: The four test groups (n = 37 each) were comparable. The incidences of vomiting in the PACU were similar. During the first 24 hr after surgery the antiemetics produced no reductions in the incidence of nausea alone or of vomiting alone. However, the combination of nausea and vomiting was reduced from 53% (placebo) to 16% (P < 0.0005), 19% (P < 0.0005) and 30% (P < 0.05) by i.m. prochlorperazine, i.v. ondansetron and i.v. prochlorperazine, respectively. The frequency of those experiencing no PONV was increased from 27% (placebo) by prochlorperazine i.m. to 57% (P < 0.01), by ondansetron i.v. to 62% (P < 0.005) and by prochlorperazine i.v. to 43% (P = NS). The onset of PONV was delayed in those given prochlorperazine im, and vomiting was less severe in those given ondansetron i.v. Headache occurred with similar frequency in each group. CONCLUSION: Prophylactic prochlorperazine 0.2 mg.kg-1 i.m. and ondansetron 0.06 mg.kg-1 i.v. are similarly efficacious in reducing nausea with vomiting after tympanoplasty, while prochlorperazine 0.1 mg.kg-1 i.v. is less efficacious. Neither drug given as described appeared to reduce the frequency of postoperative nausea alone or vomiting alone.