What are the treatment and prescription recommendations for using benzodiazepines (BZD) as muscle relaxants?

Benzodiazepines as Muscle Relaxants: Treatment and Prescription Recommendations

Benzodiazepines should not be used as first-line agents for muscle relaxation due to their significant risks of dependence, tolerance, and respiratory depression, particularly when combined with opioids. 1

FDA-Approved Indications and Mechanism of Action

• Diazepam is FDA-approved as "a useful adjunct for the relief of skeletal muscle spasm due to reflex spasm to local pathology (such as inflammation of the muscles or joints, or secondary to trauma), spasticity caused by upper motor neuron disorders (such as cerebral palsy and paraplegia), athetosis, and stiff-man syndrome" 2
• Benzodiazepines exert muscle-relaxant effects through facilitation of gamma-aminobutyric acid (GABA), an inhibitory neurotransmitter in the central nervous system 2, 3
• The effectiveness of benzodiazepines in long-term use (more than 4 months) has not been assessed by systematic clinical studies 2

Safety Concerns and Contraindications

• Benzodiazepines carry significant risks of:
  • Tolerance and dependence with prolonged use 4, 5
  • Respiratory depression, especially when combined with opioids 1, 6
  • Sedation, cognitive impairment, and increased fall risk, particularly in elderly patients 5
  • Potential for abuse and addiction 7
• The FDA added a black box warning in 2016 to both opioids and benzodiazepines recommending against co-prescribing these agents 1
• Population-based studies show that rates of death are 3- to 10-fold higher in patients co-prescribed opioids and benzodiazepines compared with opioids alone 1

Recommended Approach to Muscle Relaxation

First-Line Options

• Non-steroidal anti-inflammatory drugs (NSAIDs) should be considered first-line for conditions requiring muscle relaxation, particularly for back pain 8
• Non-pharmacological approaches should be incorporated, including physical therapy, heat/cold therapy, and appropriate exercise 8

When to Consider Benzodiazepines

• Reserve benzodiazepines for cases where other treatments have failed 1
• Short-term use only (ideally less than 4 weeks) to prevent tolerance and dependence 4
• Avoid in patients with a history of substance abuse or concurrent opioid therapy 1

Dosing Recommendations

• Start with the lowest effective dose 1
• For diazepam as muscle relaxant: 2-10 mg orally 3-4 times daily, depending on severity 2
• Limit treatment duration to the shortest period possible 4
• Taper gradually when discontinuing to avoid withdrawal symptoms 7

Special Populations

Elderly Patients

• Elimination half-life increases by approximately 1 hour for each year of age beginning with a half-life of 20 hours at 20 years of age 2
• Use lower initial doses (typically 50% of standard adult dose) 2
• Monitor closely for adverse effects including confusion, ataxia, and falls 5

Pediatric Patients

• In children, benzodiazepines should be used with extreme caution for muscle relaxation 1
• Paradoxical agitation may occur, especially in younger children 1
• Monitor oxygen saturation and be prepared to provide respiratory support 6

Monitoring and Follow-up

• Regular assessment for signs of tolerance, dependence, or misuse 4
• Monitor for respiratory depression, especially when combined with other sedative agents 6
• Have flumazenil available to reverse life-threatening respiratory depression if needed 1
• Reassess the usefulness of the drug periodically for the individual patient 2

Alternative Muscle Relaxants to Consider

• Non-benzodiazepine skeletal muscle relaxants (e.g., cyclobenzaprine, methocarbamol) may offer a more favorable risk-benefit profile 8
• For neuropathic pain with muscle spasm, consider anticonvulsants (e.g., gabapentin) 1
• For spasticity of central origin, baclofen or dantrolene may be more appropriate 9