Consequences of Chronic Chlorzoxazone Use

Adverse Effects and Recommendations

• Chronic use of chlorzoxazone is associated with potentially serious adverse effects including hepatotoxicity, central nervous system depression, and risk of abuse, and should be avoided for long-term use, especially in older adults 1
• The American Geriatrics Society identifies muscle relaxants, including chlorzoxazone, as potentially inappropriate medications for older adults due to their high risk of adverse effects, including anticholinergic effects and sedation 2
• Older adults are particularly vulnerable to the central nervous system effects of chlorzoxazone, which can increase the risk of falls and accidents 2, 3
• The 2019 AGS Beers Criteria strongly recommends avoiding muscle relaxants in older adults due to their high risk of adverse effects 2

Alternative Approaches and Efficacy

• There is insufficient evidence supporting the long-term efficacy of skeletal muscle relaxants like chlorzoxazone, with most clinical trials evaluating chlorzoxazone being short-term 1, 4
• For chronic pain management, consider NSAIDs, acetaminophen, or antidepressants as alternatives with better safety profiles for long-term use 1, 4
• If muscle relaxation is needed for spasticity rather than pain, consider agents with established efficacy for spasticity such as baclofen 3