Characterization of the analgesic activity of ketorolac in mice.

The spectrum of analgesic activity of ketorolac tromethamine was evaluated with mice exposed to the hot-plate, tail-flick and writhing tests. Morphine and indomethacin were used as representative opioid and non-steroidal analgesics respectively. Ketorolac in doses of 5 or 7.5 mg/kg i.p. was active as an analgesic in all three of the procedures. In each case, naloxone (0.5 mg/kg i.p.) significantly decreased the analgesic activity of ketorolac. It was suggested that ketorolac might act in part by causing the release of endogenous opioids.