Intravenous subdissociative-dose ketamine versus morphine for acute geriatric pain in the Emergency Department: A randomized controlled trial

Am J Emerg Med. 2019 Feb;37(2):220-227. doi: 10.1016/j.ajem.2018.05.030. Epub 2018 May 16.


Study objective: We compare the analgesic efficacy and safety of subdissociative intravenous-dose ketamine (SDK) versus morphine in geriatric Emergency Department (ED) patients.

Methods: This was a prospective, randomized, double-blind trial evaluating ED patients aged 65 and older experiencing moderate to severe acute abdominal, flank, musculoskeletal, or malignant pain. Patients were randomized to receive SDK at 0.3 mg/kg or morphine at 0.1 mg/kg by short intravenous infusion over 15 min. Evaluations occurred at 15, 30, 60, 90, and 120 min. Primary outcome was reduction in pain at 30 min. Secondary outcomes included overall rates of adverse effects and incidence of rescue analgesia.

Results: Thirty patients per group were enrolled in the study. The primary change in mean pain scores was not significantly different in the ketamine and morphine groups: 9.0 versus 8.4 at baseline (mean difference 0.6; 95% CI -0.30 to 1.43) and 4.2 versus 4.4 at 30 min (mean difference -0.2; 95% CI -1.93 to1.46). Patients in the SDK group reported higher rates of psychoperceptual adverse effects at 15, 30, and 60 min post drug administration. Two patients in the ketamine group and one in the morphine group experienced brief desaturation episodes. There were no statistically significant differences with respect to changes in vital signs and need for rescue medication.

Conclusion: SDK administered at 0.3 mg/kg over 15 min provides analgesic efficacy comparable to morphine for short-term treatment of acute pain in the geriatric ED patients but results in higher rates of psychoperceptual adverse effects. Registration #: NCT02673372.

Keywords: Analgesia; Emergency Department; Infusion; Ketamine.

Publication types

  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acute Pain / drug therapy*
  • Aged
  • Analgesia / methods
  • Analgesics, Opioid / administration & dosage*
  • Analgesics, Opioid / adverse effects
  • Anesthetics, Dissociative / administration & dosage*
  • Anesthetics, Dissociative / adverse effects
  • Double-Blind Method
  • Emergency Service, Hospital*
  • Female
  • Humans
  • Infusions, Intravenous
  • Ketamine / administration & dosage*
  • Ketamine / adverse effects
  • Male
  • Morphine / administration & dosage*
  • Morphine / adverse effects
  • Pain Management / methods
  • Pain Measurement
  • Prospective Studies


  • Analgesics, Opioid
  • Anesthetics, Dissociative
  • Ketamine
  • Morphine

Associated data