Speed of onset of analgesic effect of intravenous ketorolac compared to morphine and placebo.

The speed of onset of analgesia following intravenous ketorolac, morphine and placebo was investigated in a single-dose, double-blind, randomized, parallel group study of 105 patients. The onset of analgesia was defined as the time at which the pain intensity score reached 50% of the baseline score in 25% of patients. Post-operative patients with moderate or severe pain were dosed and followed for 1 h. Pain reduction by at least 50% occurred in 25% of patients within 40 min (placebo), 15 min (morphine 5 mg), 6 min (morphine 10 mg) and 20 min (ketorolac 10 mg). The pain reduction time for morphine (10 mg) was significantly shorter than that for ketorolac (P = 0.01) or placebo (P < 0.01).