ADDITION OF DROPERIDOL TO MORPHINE ADMINISTERED BY THE PATIENT-CONTROLLED ANALGESIA METHOD - WHAT IS THE OPTIMAL DOSE

Eighty patients were recruited into a double-blind, randomized trial t o find the optimal dose of droperidol for addition to the patient-cont rolled analgesia (PCA) morphine infusate for female patients undergoin g gynaecological surgery. A standardized anaesthetic technique was emp loyed. Post-operative analgesia was provided by PCA morphine. Patients were allocated at random into one of four treatment groups receiving with each PCA morphine bolus: (1) droperidol 0.05 mg; (2) droperidol 0 .10 mg; (3) droperidol 0.15 mg; and (4) droperidol 0.20 mg, respective ly. The incidence of post-operative nausea and vomiting (PONV), reques ts for rescue anti-emetic medication, and incidence of side effects we re recorded. The number of symptom-free patients in each group increas ed as the droperidol dose increased, but although there was a signific ant inverse association between the total dose of droperidol received and the severity of PONV (P<0.05), there were no significant differenc es between individual groups. In each group, patients were significant ly less sedated at 24 h compared with 12 h (P<0.01). However, after 24 h, patients in group 4 were significantly more sedated than patients in groups 1 and 2 (P<0.05). There were no significant differences betw een the groups in terms of the incidence of anxiety or other side effe cts attributable to droperidol. The present authors suggest that, alth ough the results demonstrate few statistically significant differences between the four groups, a PCA bolus dose of droperidol of 0.10 mg mL (-1) appears to provide the optimal balance between anti-emetic effica cy and an acceptable incidence of side effects.