Droperidol has comparable clinical efficacy against both nausea and vomiting

Background. Droperidol is commonly noted to be more effective at preventing postoperative nausea (PON) than vomiting (POV) and it is assumed to have a short duration of action. This may be relevant for clinical decisions, especially for designing multiple-drug antiemetic regimens. Methods. We conducted a post hoc analysis of a large multicentre trial. Within this trial, 1734 patients underwent inhalation anaesthesia and were randomly stratified to receive several antiemetic interventions according to a factorial design, one of which was droperidol 1.25 mg vs placebo. We considered differences to be significant when: (i) point estimates of one outcome are not within the limits of the confidence interval (CI) of the other outcome; and (ii) differences in risk ratio (also known as relative risks, RR) are at least 20%. Results. Over 24 h, nausea was reduced from 42.9% in the control to 32.0% in the droperidol group, corresponding to a relative risk (RR) of 0.75 (95% CI from 0.66 to 0.84). Vomiting was reduced from 15.6% to 11.8%, and therefore associated with a similar RR of 0.76 (0.59-0.96). In the early postoperative period (0-2 h), droperidol prevented nausea and vomiting similarly, with an RR of 0.57 (0.46-0.69) for nausea and 0.56 (0.37-0.85) for vomiting. In the late postoperative period (2-24 h), the RR was again similar with 0.83 (0.72-0.96) for nausea compared with 0.89 (0.66-1.18) for vomiting but significantly less compared with the early postoperative period. Conclusions. We conclude that droperidol prevents PON and POV equally well, yet its duration of action is short-lived.