TOPLINE:

Older adults who received baclofen or tizanidine as a muscle relaxant had a higher risk for injury than those who were prescribed cyclobenzaprine.

METHODOLOGY:

• The Beers Criteria for potentially inappropriate medication advises against using most skeletal muscle relaxants in older adults due to safety concerns. However, baclofen and tizanidine are not included in the Beers Criteria, warranting investigation into their safety.
• Researchers conducted a retrospective cohort study using data from an integrated healthcare system in southern California and included participants between ages 65 and 99 years who were prescribed baclofen, tizanidine, or cyclobenzaprine between 2008 and 2018.
• Outcomes included injury-related hospitalizations, emergency department visits, and urgent care visits documented in electronic medical records and identified through diagnostic codes for fractures, falls leading to fractures, brain injuries, and dislocation injuries, which were assessed individually and as a composite.
• Analyses included 87,896 participants (mean age, 71.4 years; 59.8% women) with 118,426 medication episodes; 54.8% participants were dispensed baclofen, 6.3% tizanidine, and 38.9% cyclobenzaprine.

TAKEAWAY:

• Researchers identified a total of 1987 injury events across medication groups, with fractures being the most common injury event (923 cases), followed by falls leading to fracture (773 cases), and other injury events (291 cases).
• Compared with cyclobenzaprine, baclofen was associated with greater risks for composite injury outcome (adjusted hazard ratio [aHR], 1.69; 95% CI, 1.51-1.88), falls leading to fracture (aHR, 1.98; 95% CI, 1.64-2.40), fractures (aHR, 1.37; 95% CI, 1.18-1.60), and brain or dislocation injuries (aHR, 2.50; 95% CI, 1.82-3.44).
• Participants prescribed tizanidine had greater risks for composite injury outcome (aHR, 1.34; 95% CI, 1.11-1.62) and falls leading to fracture (aHR, 1.58; 95% CI, 1.17-2.15) than those prescribed cyclobenzaprine.
• A history of falls, Parkinson’s disease, use of antidepressants, or kidney failure were factors independently associated with an increased risk for injury outcomes. For the composite outcome, both baclofen and tizanidine showed lower injury-free probabilities over time than cyclobenzaprine.

IN PRACTICE:

“Our findings indicate that baclofen and tizanidine do not represent safer alternatives to cyclobenzaprine for use in older adult patients with musculoskeletal complaints and should be considered for inclusion in future iterations of the AGS [American Geriatrics Society] Beers Criteria and other guidance publications,” the study authors wrote.

SOURCE:

This study was led by Monique M. George, MD, of the Department of Family Medicine at the Kaiser Permanente Woodland Hills in Los Angeles. It was published online on September 13, 2025, in the Journal of the American Geriatrics Society.

LIMITATIONS:

The retrospective study design may lead to residual confounding. The dosage and duration of muscle relaxant therapy were not assessed. Diagnostic codes were used for identifying outcomes.

DISCLOSURES:

This study was supported by a grant from the Regional Research Committee of Kaiser Permanente Southern California. No conflicts of interest were disclosed by the authors.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.