Droperidol and dimenhydrinate alone or in combination for the prevention of post-operative nausea and vomiting after nasal surgery in male patients.

Droperidol and dimenhydrinate are inexpensive antiemetic drugs. Droperidol, especially, has been studied extensively, but there are no studies on the combination of both drugs for prevention of post-operative nausea and vomiting. One hundred and forty male hospitalized patients undergoing nasal surgery were randomized to receive one of four anti-emetic regimes: placebo, dimenhydrinate (1 mg kg-1), droperidol (15 micrograms kg-1), or the combination of both drugs (droperidol 15 micrograms kg-1 + dimenhydrinate 1 mg kg-1) administered after induction of anaesthesia. Patients in the dimenhydrinate-group and the combination-group received a second dose of dimenhydrinate 6 h after the first administration to mitigate the short half-life of the drug. For general anaesthesia a standardized technique, including benzodiazepine premedication, propofol, desflurane in N2O/O2, vecuronium, and a continuous infusion of remifentanil, was used. Post-operative analgesia and anti-emetic rescue medication were standardized. Episodes of vomiting, retching, nausea, and the need for additional anti-emetics were recorded for 24 h. The main endpoint of this study was the number of patients who were completely free of post-operative nausea and vomiting (Fisher's Exact Test). Furthermore, the severity of post-operative nausea and vomiting was analysed using a standardized scoring algorithm. The incidence of patients completely free of post-operative nausea and vomiting was 62.9% in the placebo-group, 77.1% in the dimenhydrinate-group (P = 0.21), and 82.9% in the droperidol-group (P = 0.07). This increased to 94.3% in the combination-group (P = 0.0015). In all three treatment groups the severity of post-operative nausea and vomiting was reduced significantly compared with placebo treatment (P = 0.0003). The incidence of side effects was similar in the four groups. Dimenhydrinate was ineffective in reducing the incidence of post-operative nausea and vomiting and droperidol only reduced the severity of post-operative nausea and vomiting. However, the combination of both drugs significantly reduces the incidence of post-operative nausea and vomiting when compared with placebo treatment.