Cyclizine and droperidol have comparable efficacy and side effects during patient-controlled analgesia.

BACKGROUND Post-operative nausea and vomiting (PONV) is common, especially following gynaecological surgery. Patient-controlled analgesia (PCA) is frequently complicated by nausea. We assessed PONV, pain and sedation in patients receiving cyclizine or droperidol during PCA following abdominal hysterectomy in a double-blind trial. METHODS Thirty women were randomised to receive either cyclizine 0.7 mg/kg or droperidol 0.04 mg/kg during surgery followed by PCA containing morphine sulphate with cyclizine 2 mg or droperidol 0.05 mg per demand. Blinded observers scored levels of nausea, sedation, anxiety and pain. RESULTS Pain scores, PCA usage and supplemental antiemetic requirements were comparable. Nausea and sedation scores were similar in both groups. Two patients in each group developed refractory PONV. Pre-operative anxiety scores were similar and decreased comparably over time. Patients developing refractory emetic sequelae had a higher incidence of previous PONV. Previous PONV also predicted lower PCA medication intake despite similar demand rates, suggesting increased usage during lock-out periods. CONCLUSION Prophylactic cyclizine and droperidol have similar efficacy during PCA. Neither is associated with perioperative anxiety. A minority of patients have refractory PONV during PCA. Previous PONV may predict less efficient PCA usage.