There are currently three 5-hydroxytryptamine3 (5-HT3) receptor antagonists available in Australia. In this randomized, double-blind, parallel group study the prophylactic
antiemetic effect of a single dose of
tropisetron 2 mg,
ondansetron 4 mg or
dolasetron 12.5 mg was compared after major gynaecological surgery. One hundred and eighteen patients (group T n = 42; group O n = 36; group D n = 40) were evaluated for
nausea,
vomiting, recovery characteristics and satisfaction for 24 hours postoperatively. A cost-effectiveness analysis was performed. Rescue
antiemetic,
prochlorperazine 12.5 mg i.m., was given if
vomiting occurred more than 10 minutes after arrival in the recovery room. If
prochlorperazine was ineffective one hour after administration,
droperidol 1 mg i.v. was given. There were no significant differences between groups for the incidence of
vomiting during consecutive epochs until 24 hours postoperatively or overall (57%, 75% and 72.5% for groups T, O and D respectively, P = 0.18). The incidence and number of rescue antiementic treatments for
nausea or
vomiting were similar. The incidence of
nausea and the overall and interval
nausea scores were similar except for lower "worst
nausea" score in group T between 12 and 18 hours (P = 0.02). Recovery times, satisfaction and cost per patient did not differ between groups. We conclude that the risk of
postoperative nausea and vomiting remained high in this setting despite
5-HT3 receptor antagonist prophylaxis and that the choice between these agents should be based on the lowest available acquisition cost.