Parenteral ketorolac: opiate-sparing effect and lack of cardiorespiratory depression in the perioperative patient.

Two studies evaluated the intraoperative and postoperative use of ketorolac, a nonopioid analgesic. Compared with the opioid analgesic alfentanil, ketorolac administered intraoperatively exerted no adverse effects on cardirespiratory functions (i.e., no changes in heart rate, arterial partial pressure of carbon dioxide, or mean arterial pressure, and no associated apnea). Analgesic efficacy of both agents was judged to be equal. The study of postoperative infusion of ketorolac in combination with patient-controlled administration of morphine confirmed the analgesic efficacy of ketorolac when used after upper abdominal surgery. The narcotic-sparing effect was demonstrated by the finding that patients who received placebo self-administered over 40% more morphine in the first 24 hours after surgery than those in the ketorolac group. The better pain scores with ketorolac may be associated with the reduction in unpleasant morphine-related side effects or with the provision of continuous background analgesia. The lack of respiratory depression with ketorolac, which would be anticipated from its inability to bind to central opioid receptors, was also demonstrated. In the placebo group, arterial partial pressure of carbon dioxide was significantly increased postoperatively, whereas a similar increase was not found in the ketorolac group. Results of the two investigations demonstrate the absence of opioid effects with ketorolac, and support its use for intraoperative and postoperative analgesia in patients undergoing major surgery.