Single oral dose ondansetron in the prevention of postoperative nausea and emesis. The European and US Study Groups.

In two placebo-controlled, double-blind, multicentre studies, the efficacy and safety of single oral doses of ondansetron 4 mg, 8 mg and 16 mg were evaluated for the prevention of postoperative nausea and vomiting in female inpatients. For the total study populations, 26% (European study) and 32% (US study) of placebo-treated patients experienced no emesis compared with 54% (European study) and 52% (US study) of patients treated with ondansetron 16 mg, the most effective dose. Similarly, 22% (European study) and 19% (US study) of placebo-treated patients experienced no nausea compared with 42% (European study) and 34% (US study) of ondansetron 16 mg-treated patients. All ondansetron doses in both studies were statistically superior to placebo (emesis p < or = 0.007; nausea p < or = 0.033). Slightly lower percentage differences in complete response between placebo and ondansetron for both nausea and emesis were observed for patients with a previous history of postoperative nausea and emesis compared with patients with no previous history, with ondansetron 16 mg being the most effective dose for both patient groups. In the US study, a slightly greater percentage of patients undergoing non-gynaecological surgery had no nausea and no emesis compared with patients undergoing gynaecological surgery in both the placebo and ondansetron treatment groups. Again, ondansetron 16 mg was the most effective dose in both surgery types. Ondansetron was well tolerated, with only headache being reported as a significant problem in both studies.(ABSTRACT TRUNCATED AT 250 WORDS)