Prophylactic antiemetic treatment with ondansetron in children undergoing tonsillectomy

Children undergoing tonsillectomy are at high risk for postoperative vomiting. This study was undertaken to compare ondansetron with metoclopramide and droperidol for the prevention of postoperative vomiting after tonsillectomy.

Two hundred fifty-six pediatric patients, ages 2-12 years, scheduled for outpatient tonsillectomy were enrolled in a prospectively randomized, double-blinded investigation and assigned to one of four treatment regimens: placebo (saline), ondansetron 0.15 mg.kg-1, metoclopramide 0.5 mg.kg-1, or droperidol 0.075 mg.kg-1. Study drugs were administered intravenously after inhalation induction of anesthesia with halothane, nitrous oxide, and oxygen. No premedication or neuromuscular blocking agents were used. Tracheal extubation was performed while patients were still deeply anesthetized. Acetaminophen and meperidine were given for postoperative pain. Patients were observed in the recovery room for a minimum of 4 h before discharge. Parents were contacted by telephone 24 h later for follow-up.

Ondansetron reduced the incidence of postoperative emesis from 62% to 27% (relative risk 0.45, 95% confidence interval 0.29 to 0.70, P < 0.001). Metoclopramide and droperidol had no significant effect on postoperative vomiting.

The intravenous administration of ondansetron 0.15 mg.kg-1 is highly effective in reducing postoperative emesis in children undergoing tonsillectomy. Metoclopramide and droperidol at the doses tested are ineffective in this population.