Oral ondansetron in the prevention of postoperative nausea and vomiting

Abstract

The effect of three times daily oral ondansetron in preventing postoperative nausea and vomiting was investigated in two randomized, double-blind, placebo-controlled, multi-centre studies. The first study compared ondansetron 1, 8 and 16 mg to placebo, and the second study compared 8 mg ondansetron to placebo. Both studies included ASA Class I-III female patients about to undergo major abdominal gynaecological surgery or vaginal hysterectomy. In the first study, the 8 and 16 mg ondansetron groups had a significantly lower incidence of nausea and vomiting in the 0-24 h period following recovery from anaesthesia than the placebo group. Ondansetron 8 mg three times daily was also significantly better than placebo in the second study. Side-effects mainly consisted of constipation, headache, and asymptomatic elevation of liver enzymes. The incidence of side-effects was similar in ondansetron- and placebo-treated patients. There appeared to be no clinically important benefit of the 16 mg three times daily ondansetron regimen over the 8 mg three times daily dose, therefore 8 mg three times daily is recommended as the optimal oral dose in the prevention of postoperative nausea and vomiting.