Cost-effectiveness of three combinations of antiemetics in the prevention of postoperative nausea and vomiting

Background. This study compares the cost-effectiveness of three combinations of antiemetics in the prevention of postoperative nausea and vomiting (PONV). Methods. We conducted a prospective, double-blind study. Ninety ASA I-II females, 18-65 yr, undergoing general anaesthesia for major gynaecological surgery, with standardized postoperative analgesia (intrathecal 0.2 mg plus i.v. PCA morphine), were randomly assigned to receive: ondansetron 4 mg plus droperidol 1.25 mg after induction and droperidol 1.25 mg 12 h later (Group 1); dexamethasone 8 mg plus droperidol 1.25 mg after induction and droperidol 1.25 mg 12 h later (Group 2); ondansetron 4 mg plus dexamethasone 8 mg after induction and placebo 12 h later (Group 3). A decision analysis tree was used to divide each group into nine mutually exclusive subgroups, depending on the incidence of PONV, need for rescue therapy, side effects and their treatment. Direct cost and probabilities were calculated for each subgroup, then a cost-effectiveness analysis was conducted from the hospital point of view. Results. Groups 1 and 3 were more effective (80 and 70%) than Group 2 (40%, P=0.004) in preventing PONV but also more expensive. Compared with Group 2, the incremental cost per extra patient without PONV was e6.99 (95% CI, -1.26 to 36.57) for Group 1 and e13.55 (95% CI, 0.89-132.90) for Group 3. Conclusion. Ondansetron+droperidol is cheaper and at least as effective as ondansetron+ dexamethasone, and it is more effective than dexamethasone+droperidol with a reasonable extra cost.