The antiemetic efficacy of droperidol added to morphine patient-controlled analgesia: a randomized, controlled, multicenter dose-finding study

Abstract

The antiemetic dose response of droperidol when it is added to patient-controlled analgesia with morphine is not well known. We randomly allocated adults who received postoperative morphine patient-controlled analgesia (1-mg bolus, 5-min lockout) to one of four regimens: no droperidol (control) or 5, 15, or 50 micro g of droperidol per milligram of morphine. Efficacy and adverse effects were recorded during 24 h and were analyzed with number needed to treat (NNT) and number needed to harm with 95% confidence intervals. Data from 82 controls, 82 patients receiving droperidol 5 micro g, 82 receiving droperidol 15 micro g, and 83 receiving droperidol 50 micro g were analyzed. Average consumption of droperidol per 24 h was 0.2 mg with the 5- micro g regimen, 0.61 mg with the 15- micro g regimen, and 2.04 mg with the 50- micro g regimen. In controls, the incidence of nausea was 48.8%; with droperidol 5 micro g, it was 42.7% (NNT compared with control, 16 [95% confidence interval, 4.7 to -11]); with 15 micro g, it was 32.9% (NNT, 6.3 [3.3-100]); and with 50 micro g, it was 21.7% (NNT, 3.7 [2.4 to 7.6]). In controls, the incidence of vomiting was 24.4%; with droperidol 5 micro g, it was 23.2% (NNT compared with control, 82 [7 to -8.5]); with 15 micro g, it was 22.0% (NNT, 41 [6.5 to -9.6]); and with 50 micro g, it was 12% (NNT, 8.1 [4.2-142]). In controls, the incidence of pruritus was 12.2%; with droperidol 5 micro g, it was 6.1% (NNT compared with control, 16 [6.7 to -37]); and with 15 and 50 micro g, it was 2.4% (NNT, 10 [5.7-52]). In controls, the incidence of sedation was 2.4%; with droperidol 5 micro g, it was 8.5% (number needed to harm (NNH) compared with control, 16 [7.7 to -123]); with 15 micro g, it was 6.1% (NNH, 27 [10 to -40]); and with 50 micro g, it was 18.1% (NNH, 6.4 [4.1-15]). There were no extrapyramidal symptoms and no cardiac adverse events. There was no difference in patient satisfaction. The optimal antiemetic dose of droperidol is 15-50 micro g/mg of morphine. Larger doses may have more antivomiting efficacy but are likely to be unacceptably sedating.