Efficacy and Safety of Single Doses of Intramuscular Ketorolac Tromethamine Compared with Meperidine for Postoperative Pain

Ketorolac tromethamine, a potent nonnarcotic prostaglandin synthetase-inhibiting analgesic, was compared with meperidine for relief of moderate to severe postoperative pain. In a double-blind, randomized study, 125 patients received single intramuscular doses of ketorolac 30 or 90 mg or meperidine 50 or 100 mg. The degree of pain and pain relief were quantified verbally and with visual analog scales at baseline and 30 minutes, then hourly for 6 hours. Ketorolac 30 and 90 mg were significantly superior to meperidine 50 mg in six of nine efficacy measures. The onset of and peak analgesic effect of both doses of ketorolac and of meperidine were equivalent. Compared with both doses of meperidine, the two doses of ketorolac exhibited significantly longer duration of analgesic effect, as measured by the percentage of patients who terminated the study because of inadequate pain relief. The frequency of side effects was not significantly different between the drugs. The prolonged efficacy of intramuscular ketorolac combined with the reduced risk of respiratory depression suggest an important use of this drug for the relief of postoperative pain.