A Comparison of the Costs and Efficacy of Ondansetron Versus Dolasetron for Antiemetic Prophylaxis Eduardo Zarate, MD*, Mehernoor F. Watcha, MD†, Paul F. White, PhD, MD, FANZCA*, Kevin W. Klein, MD*, Monica Sa Rego, MD*, and D. Greg Stewart, MS* *Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas; and †Department of Anesthesiology and Critical Care Medicine, Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania The optimal dose and timing of 5-HT 3 antagonist ad- ministration for prophylaxis against postoperative nausea and vomiting (PONV) remains controversial. Although 5-HT 3 antagonists seem to be most effective when administered near the end of surgery, there are no data on the comparative efficacy or costs associated with the 5-HT 3 antagonists dolasetron and ondansetron when administered at the end of the operation. In this double-blinded study, 200 outpatients undergoing oto- laryngologic procedures with a standardized general anesthetic received 4 (O4) or 8 mg (O8) of ondansetron or 12.5 (D12.5) or 25 mg (D25) of dolasetron IV within 30 min before the end of surgery. A blinded observer recorded the emetic episodes, maximum nausea score, recovery room resource and drug use, nursing time spent managing PONV, times to achieve discharge cri- teria from the Phase 1 and 2 recovery units, postdis- charge emesis, and patient satisfaction. Total costs were calculated by using the perspective of a free-standing surgicenter. There were no differences in patient demo- graphics, incidence of PONV, need for rescue medica- tions, time spent in the recovery areas, unanticipated hospital admissions, or patient satisfaction among the four treatment groups. The mean total costs (95% confi- dence intervals) to prevent PONV in one patient were lowest in the D12.5 group: $23.89 (17.18 –28.79) vs $37.81 (30.29 – 45.32), $33.91 (28.92–39.35), and $75.18 (61.13– 89.24) for D25, O4, and O8, respectively. Exclud- ing nursing labor costs did not alter this finding: $18.51 (14.18 –22.85), $34.77 (28.03– 41.49), $31.77 (28.92– 39.35), and $71.76 (58.17– 85.35) for D12.5, D25, O4, and O8, respectively. We conclude that 12.5 mg of dolas- etron IV is more cost effective than 4 mg of ondansetron IV for preventing PONV after otolaryngologic surgery and is associated with similar patient satisfaction. (Anesth Analg 2000;90:1352–8) P ostoperative nausea and vomiting (PONV) is a common problem after outpatient surgery. On- dansetron, the prototype serotonin 5-HT 3 antag- onist, is safe and effective in the prophylaxis of PONV after high-risk procedures, such as otolaryngological (ENT) surgery (1). Although the manufacturer of on- dansetron has recommended that it be administered in a dose of 4 mg IV before the induction of anesthesia (2), controversy surrounds the optimal dose and tim- ing of its administration for antiemetic prophylaxis (1–5). In a meta-analysis, Tramer et al. (5) recom- mended a larger IV dose of 8 mg ondansetron for prophylaxis against PONV (5). The introduction of newer 5-HT 3 antagonists, such as dolasetron, has also led to debate regarding the relative cost-effectiveness of these compounds compared with ondansetron in routine clinical practice (6 –10). In one study (10), 50 mg of dolasetron IV (but not 25 mg IV) was as effective as 4 mg of ondansetron IV in preventing PONV when administered before the induction of anes- thesia. However, in other studies, the minimally effective dose of dolasetron was 12.5 mg IV when administered within 30 min of the end of the surgical procedure (7,9). There are also increasing data suggesting that the fre- quency and severity of the emetic episodes is decreased when ondansetron is given at the end of surgery com- pared with its administration at the induction of anes- thesia (1,4). Although there are studies comparing the efficacy of prophylactic 4 and 8 mg of ondansetron ad- ministered during the induction of anesthesia, there are no similar studies comparing the efficacy of these doses when administered at the end of surgery. Similarly, there are no data available on the comparative efficacy or costs associated with the prophylactic use of dolasetron, a less expensive alternative to ondansetron, when these drugs are administered at the end of surgery. Accepted for publication February 11, 2000. Address correspondence to Paul F. White, PhD, MD, FANZCA, Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center at Dallas, 5161 Harry Hines Blvd., CS2.126, Dallas, TX 75235-9068. Address e-mail to pwhite@mednet.swmed.edu. ©2000 by the International Anesthesia Research Society 1352 Anesth Analg 2000;90:1352–8 0003-2999/00