The effect of a 4-mg preoperative intravenous dose of ondansetron in preventing nausea and vomiting after maxillofacial surgery

Abstract

Purpose: The efficacy of a preoperative 4-mg dose of ondansetron given intravenously in preventing postoperative nausea and vomiting after maxillofacial surgery was evaluated in a double-blind randomized study.

Patients and methods: Sixteen patients had intravenous ondansetron, and an equal number had normal saline as a placebo immediately before induction of anesthesia. After intubation, a nasogastric tube was inserted, and general anaesthesia was induced with thiopentone, suxamethonium, fentanyl, nitrous oxide, enflurane, and vecuronium. Anesthesia lasted more than 1 hour in all patients. Postoperatively, episodes of vomiting were recorded, and nausea was assessed on a visual analog scale at 1, 4, and 24 hours from the time of awakening.

Results: Eight patients in the ondansetron group, compared with six in the placebo group, had nausea, and six in the ondansetron group and three in the placebo group vomited. Of the six patients who vomited in the ondansetron group, five vomited more than 8 hours from the injection of ondansetron. No significant adverse effects could be directly attributable to ondansetron.

Conclusion: Four milligrams ondansetron given intravenously preoperatively was ineffective in controlling postoperative nausea and vomiting after maxillofacial surgery. Possibly, a larger dose or a second dose given 8 hours after the first dose may be effective.