Ann Emerg Med. 2019 May;73(5):e47-e49

# Is Low-Dose Ketamine an Effective Alternative to Opioids for Acute Pain?

Kirschner J, Hunter B

Summary: In adult emergency department (ED) patients with acute pain, low-dose intravenous ketamine (0.3 to 0.5 mg/kg) may provide pain relief within 10 minutes that is similar to that of single-dose intravenous morphine (0.1 mg/kg).

Data Sources: A medical librarian searched MEDLINE, EMBASE, Scopus, Cochrane Database of Systematic Reviews, and Database of Abstracts of Reviews of Effects from inception through February 2017. The Cochrane Central Register of Controlled Trials, ClinicalTrials.gov, and the World Health Organization International Clinical Trials Registry Platform were searched for gray literature, and bibliographies were searched for additional citations. Only English-language studies were included.

Study Selection: Two reviewers screened all titles and abstracts, and discrepancies were resolved by discussion or an adjudicator. Included studies were randomized trials of low-dose intravenous ketamine less than or equal to 0.5 mg/kg compared with intravenous opioids in adult ED patients with acute pain (≤1 week’s duration). Studies had to report a change in either a visual analog scale or numeric rating scale score within 60 minutes.

Data Extraction and Synthesis: Mean visual analog scale or numeric rating scale score, mean changes, and SDs were abstracted for all points less than or equal to 120 minutes, although details of data abstraction were not reported. The primary outcome was change in mean pain score at 10 minutes or closest point to 10 minutes with available data. The secondary outcome of adverse events was not predefined, but all adverse events reported in the individual trials were recorded. The difference in change in visual analog scale or numeric rating scale score between ketamine and opioids was meta-analyzed with random-effects models. Results were reported with 95% confidence intervals. The quality of individual trials was assessed with the Cochrane Risk of Bias Tool.