Comparison of ketorolac, pentazocine, and placebo in treating postoperative pain

In a single-dose, randomized, double-blind, double-observer, and placebo-controlled study, the analgesic efficacy and safety of ketorolac tromethamine (ketorolac), a novel nonnarcotic agent, and pentazocine were compared in 160 patients with postoperative pain. Patients with moderate-to-very severe pain after major surgery received a single intramuscular injection of ketorolac 10 mg (38 patients), ketorolac 30 mg (40 patients), pentazocine 30 mg (41 patients), or placebo (41 patients). Ketorolac 30 mg was superior to the other treatments in the overall global assessments by the patients and by the investigators. Cumulative ratings of pain severity and pain relief over six and eight hours after drug administration also showed ketorolac 30 mg to be significantly superior to pentazocine 30 mg (P < 0.05). Assessment of pain intensity at 2, 3, and 4 hours showed ketorolac 10 mg to be significantly superior to placebo (P < 0.05). The superior efficacy of both ketorolac regimens compared with pentazocine 30 mg or placebo was confirmed by the pain relief scores, particularly from two to eight hours postdose. No serious adverse events were reported by patients or observed by the investigators, and the incidence of adverse events - mostly somnolence - was similar in the four treatment groups. This comparative study showed intramuscular ketorolac 30 mg to be more effective for postoperative analgesia than ketorolac 10 mg, pentazocine 30 mg, or placebo.