Double-blind comparison of the morphine sparing effect of continuous and intermittent i.m. administration of ketorolac.

The morphine sparing effect of ketorolac 10 mg administered 4-hourly by intermittent i.m. injection was compared with a continuous i.m. infusion in a double-blind, placebo-controlled trial in patients undergoing upper abdominal surgery. During the 48-h postoperative period, each patient was provided with a patient-controlled analgesia (PCA) system which delivered bolus doses of morphine and administered the intermittent i.m. doses automatically via a computer controlled pump. In the first 24 h after surgery, there was a significant reduction in morphine demanded by both groups receiving ketorolac compared with placebo. Patients who received a continuous infusion of ketorolac after abdominal surgery required a median dose of morphine by PCA which was 49% less than controls. In the second 24 h and over the entire 48 h of the study, patients in the continuous group required significantly less morphine than those in the placebo group. The intermittent group used less than the placebo group, but this was not significant.