(959) Exploring the Link Between Intravenous Methocarbamol and Acute Kidney Injury

Monday, February 24, 2025

2:30pm – 3:30pm Eastern Time

Location: Connections Central - RST 06

First Author(s)

ML

Matthew Li, PharmD, MHA, BCPS, BCCCP (he/him/his)

Westchester Medical Center
Valhalla, New York, USA

Co-Author(s)

PD

Philip Dudley, MD

Resident
Westchester Medical Center, United States
AW

Avery Wilson, MD

Resident
Westchester Medical Center, United States
TD

Tyler D'agostino, MD

Resident
Westchester Medical Center, United States
DB

Darrel Brennen, MBBS

Resident
Westchester Medical Center, United States
AV

Andrew Villion, MD

Critical Care Anesthesiology Attending Physician
Westchester Medical Center
Valhalla
MB

Matthew Bronstein, MD

Medical Director, Trauma Intensive Care Unit
Westchester Medical Center, United States

Introduction: Methocarbamol is a central nervous system depressant used for its skeletal muscle relaxant properties as part of a multimodal analgesia regimen. Intravenous (IV) methocarbamol contains polyethylene glycol (PEG) 300 which has been associated with acute tubular necrosis. The IV methocarbamol package insert states there is a maximum consecutive duration of therapy of 3 days followed by a drug-free interval of 48 hours. The incidence of clinically significant acute kidney injury (AKI) with IV methocarbamol is not well described.

Methods: This is a single-center retrospective evaluation of adult patients admitted to the trauma or surgical intensive care unit (ICU) that received IV methocarbamol between October 2020 and April 2024. The primary outcome was serum creatinine (SCr) trend through day 7 after IV methocarbamol initiation and was evaluated using the Kruskal-Wallis Test. Secondary analyses included multiple linear regression with SCr as the dependent variable and Wilcoxon Rank-Sum Tests comparing SCr between patients who did and did not receive a drug-free interval. Statistical analyses were performed using RStudio 2024.04.2 (Vienna, Austria).

Results: A total of 68 patients met inclusion criteria. Four patients received consecutive courses of IV methocarbamol without a drug-free interval. There were no differences between the median (IQR) SCr (mg/dL) from day 1 of IV methocarbamol initiation through day 7 in the entire cohort [0.83 (0.71, 1.08) vs 0.74 (0.62, 1.33), P = 0.55] and in patients without a drug-free interval [1.04 (0.89, 2.56) vs. 1.20 (0.79, 2.92), P = 0.84]. Multiple linear regression analyses identified age as the only significant predictor of increased SCr (P = 0.02). Median SCr was not different in patients who did or did not receive a drug-free interval between courses, except on day 6 after IV methocarbamol initiation [1.30 (0.87, 2.95) vs. 0.73 (0.59, 1.36), P = 0.03].

Conclusions: IV methocarbamol was not associated with an increase in SCr in critically ill patients through day 7 of therapy. Patients without a drug-free interval had a higher SCr on day 6. Larger studies are needed to further delineate the relationship between IV methocarbamol and AKI.