Purpose: Recent warnings regarding the safety of droperidol have limited use of this drug as an antiemetic. Haloperidol, a butyrophenone derivative similar to droperidol, has not been rigorously evaluated as an antiemetic. The aim of this study was to compare the prophylactic antiemetic efficacy of haloperidol vs ondansetron for the prevention of postoperative nausea and vomiting (PONV) after general anesthesia.Methods: Ninety non-smoking female patients were eligible to participate in this randomized double-blinded study. Approximately 30 min before the end of surgery, patients were randomly assigned to receive either haloperidol 2 mg iv, or ondansetron 4 mg iv, respectively. The incidence of PONV, average pain and sedation scores, recovery times, and changes of the rate-corrected QT (QTc) interval were observed postoperatively. Results:The proportion of patients who experienced PONV in the first 24 hr was similar in the two groups (28% and 26% for haloperidol and ondansetron groups, respectively). The incidence of PONV was significantly less in both groups than predicted according to the patients' underlying risks (53% for the haloperidol group, P = 0.016; 51% for the ondansetron group, P = 0.015). Pain scores, sedation scores, and recovery times were similar in the two groups, and no prolongation of the QTc interval was observed in either group. Conclusions: Haloperidol 2 mg iv given 30 min before the end of surgery is effective in preventing PONV, with efficacy comparable to ondansetron 4 mg iv for the first 24 hr after general anesthesia.

Purpose: Postoperative nausea and vomiting (PONV) occurs frequently after general anesthesia. We evaluated the timing of 2 mg iv doses of haloperidol on the efficacy of this drug as a prophylactic antiemetic for PONV. Methods: Ninety-four non-smoking female patients with a history of motion sickness and/or PONV (Apfel's simplified risk score = 3; predicted incidence of PONV = 60%) were eligible to participate in this randomized, double-blind study. Patients were divided into two groups. Group 1 patients received haloperidol 2 mg iv during induction of anesthesia. Group 2 patients received haloperidol 2 mg iv approximately 30 min before the end of surgery. The occurrence of nausea and vomiting, nausea scores, pain scores, sedation levels, and adverse effects (cardiac arrhythmias, and extrapyramidal effects) were recorded by a trained, blinded investigator. Results:The percentages of patients who experienced PONV in the first 24 hr were similar for the two groups (Group 1 = 30%; Group 2 = 26%, P = 0.645). The incidence of PONV was significantly smaller in both groups than that predicted (60%) according to the patients' underlying risks (Group 1, P = 0.004; Group 2, P = 0.001). Nausea scores, pain scores, sedation scores, emergence times, and time to first rescue treatment were similar in the two groups. No adverse effects attributable to the study medication were observed. Conclusion:The timing of administration of haloperidol 2 mg iv does not influence its antiemetic efficacy. The recovery profiles were also similar whether haloperidol was administered at the start, or at the end of surgery. Reports of Original InvestigationsThe timing of haloperidol administration does not affect its prophylactic antiemetic efficacy Address correspondence to: Dr. Yi Lee, Department of Anesthesiology, Buddhist Tzu-Chi Medical Center, Buddhist Tzu-Chi University School of Medicine, No. 707, Section 3, Chung-Yang Road, Hualien, Taiwan, ROC. E-mail: drleeyi2001@yahoo.com.tw There were no direct funding sources (departmental, hospital, institutional, commercial) supporting this work. There are no commercial or non-commercial affiliations that were, or might be perceived to be, a conflict of interest amongst the authors relating to publication of the data. The clinical trial registration number (Buddhist Tzu Chi Medical Center): IRB094-41.