The study compared patients given-low-dose ketamine with those given morphine for acute pain relief.
A recent review and meta-analysis found that low-dose ketamine (LDK) can be used in place of opioids for patients in acute pain seeking care in the emergency department (ED).
Ketamine, given by infusion, is an old drug that been used since the 1960s for chronic pain; in 2018 3 pain societies released guidelines for its use in both acute and chronic pain.
This report looked at the proportion of patients who experienced nausea and hypoxia (the safety profile) and pain control as well as the need for rescue pain relief (effectiveness) in LDK compared with morphine.
The systematic review and meta-analysis of 8 randomized controlled trials, winnowed down from 524 studies found in Medline and EMBASE, found similar results as previous studies, the authors said.
Data were pooled using random-effects models and reported as mean differences and risk ratios (RR) at 95% confidence intervals (CIs) and researchers used the Grading of Recommendations Assessment, Development and Evaluation (GRADE) framework to assess the certainty of the evidence.
Out of a total of 1191 patients, 598 were given LDK and 593 received morphine; the authors found no significant difference in reported mean pain scores between the two within the first 60 minutes after pain relief was give. At 60 to 120 minutes, there was a slight difference in pain scores in favor of morphine.
The need for rescue medication was also similar between groups (RR = 1.26; 95% CI, 0.50-3.16), as was the proportion of patients who experienced nausea (RR = 0.97; 95% CI, 0.63-1.49) and hypoxia (RR = 0.38; 95% CI, 0.10-1.41).
The doses of LDK that were used in the included studies varied from 0.2 to 0.5mg/kg, and the authors noted that dosing differences may have affected study results.
All outcomes were judged to have low certainty in the evidence (out of very low, low, moderate or high).
The study had several limitations common to all systematic reviews and meta‐analyses in that the results were limited by the quality of the included trials.
Ketamine's possible adverse events include laryngospasm, hypertension, tachycardia, and emergence reactions.
Balzer N, McLeod S, Walsh C, Grewal KG. Low‐dose ketamine for acute pain control in the emergency department: A systematic review and meta‐analysis. Acad Emerg Med. Published online October 24, 2020. Doi: 10.1111/acem.14159