1. 2025;28;E255-E261Retrospective Analysis of Liver Function Post Intravenous Ketamine for Treating Complex Regional Pain Syndrome
   Retrospective Study
   Chanbin Lee, BA, Philip Getson, DO, Neel Mehta, MD, Jay Joshi, MD, and Pradeep Chopra, MD.

BACKGROUND: Complex Regional Pain Syndrome (CRPS) is a severely painful condition with very few effective treatments. One of the treatments used to treat CRPS is intravenous ketamine infusions. There has been one controversial anecdotal report on the effect of ketamine on liver dysfunction.

OBJECTIVES: This study aimed to determine the effect of ketamine on liver enzymes.

STUDY DESIGN: A retrospective study.

SETTING: Multilocation Pain Management Centers.

METHODS: During the treatment period from January 2010 through December 2018, the medical records of 52 patients were reviewed and analyzed. All of them had undergone an intravenous ketamine infusion for managing CRPS. As per protocol, a liver function test was performed within 24 hours postinfusion. The Brown University Human Research Protection Program determined that the proposed research did not involve human subjects as defined by 45 CFR Part 46.102.

RESULTS: A retrospective chart review was performed as part of ongoing quality assessment. All of the patients had received multiple days of a loading dose of ketamine infusion varying from 7 days to 10 days and received subsequent booster infusions varying from one day to 2 days. All the infusion days were limited to 4 hours each day. All the patients reported at least 50% pain relief lasting for more than 4 weeks to 6 weeks. Out of the 52 patients studied, 36 (69%) had returned to work or resumed attending school. Blood liver function tests were performed within 24 hours of the infusion. The liver function tests performed were serum albumin, total protein, total bilirubin, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase levels. There was no evidence of liver dysfunction in any of the patients following their ketamine infusion.

LIMITATIONS: This was a retrospective analysis without a control group.

CONCLUSIONS: Intravenous ketamine infusions performed to achieve adequate pain control for CRPS does not alter liver function tests.

KEY WORDS: CRPS, Complex Regional Pain Syndrome, liver enzymes, ketamine, liver function test