What is the best muscle relaxant for the elderly?

From the Guidelines

For elderly patients, cyclobenzaprine (Flexeril) at a reduced dose of 5 mg once or twice daily is often considered the best muscle relaxant option. This medication should be used for short durations, typically 7-10 days, to minimize side effects 1. Other good options include methocarbamol (Robaxin) at 500-750 mg three to four times daily or tizanidine (Zanaflex) starting at 2 mg at bedtime. Elderly patients should generally avoid carisoprodol (Soma) due to its high addiction potential and baclofen due to its significant central nervous system effects. When prescribing muscle relaxants to the elderly, start with the lowest possible dose and monitor closely for side effects like sedation, confusion, dry mouth, and urinary retention. Non-pharmacological approaches should be tried first, including physical therapy, gentle stretching, heat therapy, and massage. The reason for this cautious approach is that elderly patients have altered drug metabolism, increased sensitivity to central nervous system depressants, and are at higher risk for falls and cognitive impairment with these medications.

Some key points to consider when prescribing muscle relaxants to the elderly include:

• Starting with the lowest possible dose to minimize side effects
• Monitoring closely for side effects like sedation, confusion, dry mouth, and urinary retention
• Avoiding carisoprodol (Soma) due to its high addiction potential
• Avoiding baclofen due to its significant central nervous system effects
• Trying non-pharmacological approaches first, including physical therapy, gentle stretching, heat therapy, and massage
• Being aware of the potential for altered drug metabolism and increased sensitivity to central nervous system depressants in elderly patients.

It's also important to note that there is no compelling evidence that skeletal muscle relaxants differ in efficacy or safety 1, but risk-benefit profiles could vary substantially due to differences in pharmacology. Therefore, it's essential to carefully weigh the potential benefits and harms of each medication and consider individual patient factors when making treatment decisions.

From the Research

Best Muscle Relaxant for the Elderly

The best muscle relaxant for the elderly can be determined by considering the safety and efficacy of various options.

• Tizanidine is a centrally acting alpha-2 adrenoceptor agonist with both antispastic and antispasmodic activity, showing efficacy in common indications for all skeletal muscle relaxants (SMRs) 2.
• It has a lower incidence of adverse events, such as injury, delirium, encephalopathy, falls, and opioid overdose, compared to other SMRs like baclofen 2.
• Tizanidine also has no association with the risk of Alzheimer's disease, unlike orphenadrine, and no risk of serotonin syndrome like metaxalone when co-medicated with serotonergic drugs 2.
• A study comparing tizanidine with baclofen in the treatment of chronic spasticity in multiple sclerosis found that tizanidine provided a new therapeutic alternative with similar antispastic effects and improved muscle strength, bladder function, and activities of daily living 3.
• Another study evaluating the treatment of back pain with tizanidine and NSAIDs found that tizanidine resulted in quick pain relief, with initial relief on the 2nd day of treatment and complete relief after 4 days, and was well-tolerated with rare and transient adverse effects 4.
• A systematic review of skeletal muscle relaxants for spasticity and musculoskeletal conditions found that tizanidine was effective compared to placebo in patients with spasticity and musculoskeletal conditions, with fair evidence of its efficacy and safety 5.

Safety Considerations

When considering the best muscle relaxant for the elderly, safety is a crucial factor.

• Tizanidine has been found to have a lower risk of adverse events, such as falls and opioid overdose, compared to other SMRs 2.
• However, it is essential to be aware of the potential risks of tizanidine overdose, which can include lethargy, bradycardia, hypotension, agitation, confusion, vomiting, and coma 6.
• The dosage of tizanidine should be carefully monitored, especially in elderly patients, to minimize the risk of adverse events.

Comparison with Other Muscle Relaxants

Comparing tizanidine with other muscle relaxants can help determine its suitability for elderly patients.

• Tizanidine has been found to be roughly equivalent to baclofen in terms of efficacy for spasticity, but with a different adverse event profile 5.
• Cyclobenzaprine, carisoprodol, and orphenadrine have also been found to be effective for musculoskeletal conditions, but with varying adverse event profiles 5.
• The choice of muscle relaxant should be based on individual patient needs and medical history, taking into account the potential benefits and risks of each option 2, 5.