Low-Dose Ketamine Provides Comparable Acute Pain Relief, More Adverse Events Than Morphine
Ketamine treatment in the emergency department may be associated with a higher rate of self-limited neuropsychological adverse events compared with morphine.
According to the results of a systematic review published in the Annals of Emergency Medicine, acute pain management in the emergency department with low-dose ketamine may provide pain relief comparable with morphine at 30 minutes, but may be associated with a higher rate of self-limited neuropsychological adverse events.
In this systematic review of 6 randomized controlled trials and 2 observational studies (n=225), researchers evaluated the use of ketamine alone or as an adjunct for acute pain management in the emergency department. Pain control, the need for opioid analgesics, and the occurrence of adverse events were compared in patients who received ketamine vs opioids.
Moderate-quality evidence from the randomized controlled trials in which low-dose ketamine (0.1-0.5 mg/kg) administered intravenously was compared with intravenous morphine (0.05-0.1 mg/kg) indicated comparable pain scores in the two treatment groups.
The researchers were unable to assess whether ketamine use led to a reduced need for opioid analgesics due to limited data from the 3 studies that assessed this outcome.
Low-dose ketamine was associated with increased self-limited adverse events compared with opioids (15.4% vs 4.4%). Agitation, hallucinations, dysphoria, and confusion were reported as adverse events. No difference in rates of respiratory depression was reported in either group.
In an editorial commentary published in the Annals of Emergency Medicine, researchers noted that the review "provides preliminary evidence that low-dose ketamine may be used as an alternative to opioids for acute pain in the [emergency department] setting." They noted, however, that "studies with larger sample sizes and more rigorous methodology are needed to establish patient selection criteria and the best dosing strategy."
Gottlieb M, Ryan KW, Binkley C. Is low-dose ketamine an effective alternative to opioids for the treatment of acute pain in the emergency department [published online December 8, 2017]? Ann Emerg Med. doi:10.1016/j.annemergmed.2017.10.028