Low-dose ketamine combined with morphine in the hospital emergency department relieves pain and improves trauma patients' satisfaction

Background and objective: Pain control is a critical aspect of trauma care in hospital emergency departments. Ketamine is an antagonist of the N-methyl-D-aspartate receptor and co-administration may enhance the effect of opioids. We aimed to compare the efficacy of a morphine-ketamine combination to a morphine-placebo combination in trauma patients. Methods: Multicenter, randomized, double-blind trial. Block randomization was used to assign 220 patients with severe acute pain in 3 hospital emergency departments. One group received the standard dose of 0.1 mg/kg of morphine combined with 0.1 mg/kg of ketamine. The other group received 0.1 mg/kg of morphine with placebo. Effective analgesia was defined by a numerical pain score of 3 or less on a pain scale. Pain severity and patient satisfaction were assessed until 120 minutes after dosing. The data were analyzed on an intention-to-treat basis. Results: Pain was better controlled in the morphine-ketamine group 10 and 30 minutes after administration of the combination (P<.05) and fewer patients required a second analgesic dose (21.8% vs 39.4% in the placebo group, P=.007). The mean (SD) total morphine consumption was 8.29 (3.2) mg in the ketannine group and 9.54 (3.41 mg) in the placebo group (P=.008); the analgesic effect in the ketamine group was superior at 30 minutes (P<.001). Conclusion: The combination of morphine and ketamine provides effective analgesia for hospital emergency department trauma patients with severe acute pain.