According to Academic Emergency Medicine, a Systematic Review and Meta-analysis highlighted that Ketamine is not inferior to morphine for easing acute pain. It indicated that ketamine could be considered as a substitute to opioids for ED short-term pain control.
For acute pain treatment, opioids are usually prescribed in the emergency department (ED). Analgesic substitutes are being investigated in response to an epidemic of opioid misuse. One such opioid substitute is the Low-dose ketamine (LDK) for the acute pain treatment in the ED.

Karlow N et al. performed a systematic review and meta-analysis to explain whether LDK is an efficacious and safe opioid substitute to reduce acute pain in adults in the ED setting.
In this systematic review of randomized controlled trials, intravenous opioids were compared to LDK for acute pain relief in the ED. The studies where the control group primarily received opioids prior to ketamine were not considered. An electronic search technique was designed by a research librarian. The changes in visual analog scale (VAS) or numeric rating scale (NRS) pain scales were examined to determine the relative effects of LDK and opioids in the treatment of acute pain.

In this meta-analysis, 3 studies met the inclusion criteria. Ketamine was not inferior (relative reduction = 0.42, 95% confidence interval = -0.70 to 1.54) as compared to to pain scale reduction with morphine. All in all, no severe adverse events were reported in any study, but higher rates of non-severe adverse events were noticed with ketamine. Thus it was concluded that the low dose ketamine can be considered as an alternative to opioids for Emergency Department short-term pain control.