Intravenous ketorolac and subarachnoid opioid analgesia in the management of acute postoperative pain.

BACKGROUND AND OBJECTIVES

Ketorolac is a parenteral nonsteroidal anti-inflammatory drug that provides analgesia through a peripheral mechanism. The purpose of this study was to evaluate whether the scheduled administration of intravenous ketorolac improves the analgesia provided by subarachnoid opioids after surgery.

METHODS

Patients undergoing major urologic surgery were enrolled in a randomized, placebo-controlled, double-blinded study and received one of two analgesic regimens. All patients were given subarachnoid opioid analgesia consisting of morphine (range, 0.55-0.8 mg) plus fentanyl (25 micrograms) at the completion of surgery just prior to awakening. In addition to subarachnoid opioids, patients received four doses of either intravenous placebo (group 1, n = 21) or ketorolac (group 2, n = 17) administered 30 minutes before the anticipated completion of surgery and at 6, 12, and 18 hours after surgery. Patients in group 2 who were 65 years old or older received 30 mg ketorolac initially, with subsequent doses of 15 mg. Those younger than 65 years of age received 60 mg ketorolac initially, with subsequent doses of 30 mg. Pain scores were assessed by a blinded observer using a 10-cm visual analog scale (VAS) at 1, 8, and 24 hours after the operation. Intravenous morphine requirements while in the postanesthesia care unit (PACU) and during the following 24 hours, as well as the incidence of pruritus, nausea, naloxone usage, and bleeding were also recorded. Results were analyzed using the Wilcoxon rank-sum, Fischer's exact, chi-square, and Student's t tests.

RESULTS

Patients receiving intravenous ketorolac (group 2) in addition to subarachnoid opioids had significantly lower pain scores 1 hour after surgery, and required less supplementary intravenous morphine within the first 24 postoperative hours (P < .05). The percentage of patients requiring no analgesic intervention while in the PACU was significantly higher for those receiving ketorolac (P = .01). The incidence of opioid-related side effects was similar between groups, and no perioperative bleeding was observed.

CONCLUSIONS

When used in conjunction with subarachnoid opioids, the scheduled administration of intravenous ketorolac during the first 24 hours after major urologic surgery significantly enhances analgesia and reduces the need for supplemental intravenous opioids without affecting the incidence of side effects. Intravenous ketorolac is a safe and useful adjuvant to subarachnoid opioids in the management of acute postoperative pain.