Dexamethasone has additive effect when combined with ondansetron and droperidol for treatment of established PONV.

Prophylactic dexamethasone, ondansetron and droperidol have a documented effect on post-operative nausea and vomiting (PONV). Still, there is a lack of studies investigating the effect of adding dexamethasone to ondansetron and droperidol in order to treat established PONV. In this double-blind randomised, controlled trial, we compared triple prophylaxis for PONV consisting of dexamethasone 8 mg intravenous (IV), ondansetron 4 mg IV and droperidol 0.625 mg IV (n = 157) with placebo (n = 156) given before gynaecological day-case surgery. Subsequently, in those having PONV despite triple prophylaxis or placebo, a dose of ondansetron and droperidol plus dexamethasone was compared with the combination of ondansetron and droperidol. Triple prophylaxis reduced acute PONV (0-6 h) (P = 0.0003) and post-discharge PONV (6-24 h) (P = 0.001) when compared with placebo. Among those suffering from PONV despite placebo or active prophylaxis (n = 80), adding dexamethasone to ondansetron and droperidol reduced acute PONV (0-6 h) (P = 0.025) as well as post-discharge nausea (6-24 h) (P = 0.04) compared with duo treatment comprising ondansetron and droperidol. In those reporting PONV despite prophylaxis (n = 12), the treatment comprising ondansetron and droperidol, with or without dexamethasone, gave a 91.7% reduction in acute PONV and an 83.6% reduction in post-discharge PONV. Treatment of established PONV comprising ondansetron and droperidol, with or without dexamethasone, reduced PONV in both treatment groups. In those reporting PONV without active prophylaxis, the addition of dexamethasone resulted in a significant amplification of the PONV-reducing [corrected] effects of ondansetron and droperidol.