The dose-response relation and cost-effectiveness of granisetron for the prophylaxis of pediatric postoperative emesis

Background: Postoperative nausea and vomiting (PONV) may delay discharge from hospital after ambulatory surgery. The antiserotonin agents, ondansetron and granisetron, provide effective prophylaxis against chemotherapy-induced and postoperative nausea and vomiting in adults, but are expensive. We determined the dose-response relation of granisetron and the financial impact of using this drug in preventing PONV after pediatric outpatient surgery. Methods: In a randomized, double-blind, placebo-controlled study, 97 pediatric outpatients received a placebo or 10 or 40 μg · kg ^-1 granisetron intravenously during a standardized anesthetic. Episodes of postoperative retching, vomiting, and times to discharge readiness were recorded. A decision analysis tree was used to divide each study group into nine mutually exclusive subgroups, depending on the incidence of PONV, need for rescue therapy, and the side effects of antiemetics. Costs and probabilities were assigned to each subgroup, and the cost-effectiveness ratio was determined by dividing the sum of these weighted costs by the number of patients free from both PONV and antiemetic side effects. Results: Granisetron (40 μg · kg ^-1 intravenously) was more effective than a placebo or 10 μg · kg ^-1 granisetron in decreasing the incidence and frequency of postoperative emesis, both in the ambulatory surgery center and during the first 24 h. Patients receiving 40 μg · kg ^-1 granisetron also had shorter times to discharge readiness compared with those receiving a placebo. Administering this dose of granisetron to all high-risk patients would cost the ambulatory care center an additional $99 (95% CI, range $89- $112) per emesis-free patient if nursing labor costs are excluded and $101 (95% CI, range $91-$113) if nursing costs are included. Conclusions: In this study, 40 μg · kg ^-1 intravenous granisetron (but not 10 μg · kg ^-1) provided effective prophylaxis in children against PONV compared with a placebo, but at a high cost. The effective dose of granisetron for PONV prophylaxis is higher than the Food and Drug Administration-recommended dose for chemotherapy-induced emesis.