Placebo-controlled comparison of single intramuscular doses of ketorolac tromethamine and pethidine for post-operative analgesia.

The analgesic efficacy and safety of single doses of 10 mg and 30 mg ketorolac tromethamine and 100 mg pethidine were evaluated in a double-blind, parallel-group study. The drugs were administered intramuscularly to patients experiencing moderate, severe or very severe pain immediately following major abdominal surgery. A total of 129 patients were randomly assigned to receive either active drug (n = 32 for each treatment group) or placebo (n = 33), and the patients assessed pain intensity and pain relief on a visual analogue scale at regular intervals over the following 8 h. During the first 2 h, pethidine had a more rapid onset of action than ketorolac or placebo, and thereafter 100 mg pethidine and 30 mg ketorolac were equally effective. Ketorolac, at a dose of 10 or 30 mg, and 100 mg pethidine were clinically and statistically more effective than placebo, with 30 mg ketorolac having a similar efficacy to 100 mg pethidine over the 8-h study period and 10 mg ketorolac being slightly less effective than 30 mg ketorolac. No serious adverse events were reported.