Ketamine Is Effective Adjunct to Morphine for Controlling Acute Pain

Authors: Sin B et al., J Emerg Med 2017 Mar 6;

Morphine plus ketamine performed better than morphine alone in this randomized, double-blind study.

Researchers performed a double-blind, randomized, placebo-controlled trial to evaluate the safety and effectiveness of subdissociative dose ketamine as an adjunct to morphine for acute pain. Sixty adult patients presenting to a level II community teaching hospital with acute pain (defined as pain with a duration of 15 days or less) were randomized to receive 0.1 mg/kg of morphine plus either 0.3 mg/kg of ketamine or placebo infused over 15 minutes. Pain was assessed on a traditional 10-point scale before administration and every 15 minutes after administration for up to 2 hours.

Pain scores were significantly lower in the morphine/ketamine group than in the morphine/placebo group at both 15 minutes (median scores, 3.6 vs. 6.0) and 30 minutes (3.0 vs. 5.0) after administration. There was no statistically significant difference in adverse events between groups and no occurrence of emergence phenomena in the ketamine group. Patients in the ketamine group also reported a higher rate of satisfaction with pain control (mean satisfaction score, 8.57 vs. 6.05 on a 10-point Likert scale).

Comment

As one would expect, patients received better analgesia and had higher satisfaction with their pain control when morphine was used in conjunction with ketamine. Important to note is that not only was pain control improved, but also there were no associated untoward events. Clinicians should consider using these medications in combination to control acute pain in the emergency department, especially in patients who have challenging pain syndromes.