The morphine sparing effect of ketorolac tromethamine

Abstract

A randomised, double‐blind study of patients after upper abdominal surgery was undertaken to assess the analgesic efficacy of ketorolac tromethamine, a new, parenteral non‐steroidal anti‐inflammatory agent. Postoperatively, patients received a 24‐hour intramuscular infusion of either saline (n = 20), ketorolac 1.5 mg/hour (n = 21) or ketorolac 3.0 mg/hour (n = 20). Cumulative morphine requirements were measured using a patient‐controlled analgesia system which delivered intravenous increments of morphine on demand. Pain was assessed by visual analogue scores. Arterial blood gas analyses were performed pre‐operatively and on the first postoperative day.Patients who received low and high dose ketorolac infusions required less morphine than the control group (p < 0.05 and p = 0.06, respectively). This was associated with significantly lower pain scores. Patients who received the higher ketorolac dose had significantly less postoperative increase in arterial carbon dioxide tensions than controls. This study suggests that ketorolac tromethamine is a useful analgesic drug with significant morphine sparing properties.