Effect of timing of ketorolac administration on patient-controlled opioid use.
In order to investigate the analgesic effect of timing of administration of ketorolac 10 mg i.v., we recorded patient-controlled use of diamorphine at 2, 4 and 12 h after abdominal hysterectomy. In a randomized, double-blind trial, 30 patients received ketorolac before skin incision and 28 after skin closure. A control group of 32 patients did not receive ketorolac. We measured operative blood loss and assessed nausea, vomiting and pruritus. After 2 h of patient-controlled analgesia, the median cumulative diamorphine dose in the group given ketorolac before operation was less than that of the control group (95% confidence interval 8-66 micrograms kg-1; P = 0.01). There were no other statistically significant differences in diamorphine consumption between the groups. The frequency of nausea and vomiting was similar in all groups Median blood loss in the group given ketorolac before operation exceeded that of the patients who did not receive ketorolac before operation (95% confidence interval 20-149 ml; P = 0.01). We conclude that the diamorphine-sparing effect of ketorolac attributable to timing of administration was small, conferred no clinical benefit and was accompanied by increased bleeding. No patient given ketorolac complained of pruritus.