From the Guidelines
For elderly patients requiring muscle relaxants, methocarbamol (500mg three to four times daily) is generally the preferred option due to its fewer central nervous system effects, as evidenced by the lack of strong anticholinergic properties compared to other muscle relaxants like cyclobenzaprine 1. When considering muscle relaxants for elderly patients, it's essential to prioritize non-pharmacological approaches first, including:
- Physical therapy
- Heat therapy
- Gentle stretching
- Massage These approaches can help minimize the need for medication and reduce the risk of adverse effects.
In cases where medication is necessary, methocarbamol is a reasonable choice due to its relatively favorable side effect profile. However, it's crucial to:
- Start with a low dose
- Monitor closely for side effects like sedation, confusion, and falls
- Limit treatment duration to minimize risks
- Be aware of the potential for drug interactions due to polypharmacy, as highlighted in a 2021 study on polypharmacy management in older patients 1.
Other options like cyclobenzaprine, baclofen, and tizanidine may be considered, but their use should be carefully weighed against the potential risks, particularly in elderly patients with increased sensitivity to medication side effects and reduced drug clearance due to age-related changes in liver and kidney function. A 2007 review of medications for acute and chronic low back pain found that skeletal muscle relaxants were associated with a higher total number of adverse events and central nervous system adverse events compared to placebo 1.
From the FDA Drug Label
No specific pharmacokinetic study was conducted to investigate age effects. Cross study comparison of pharmacokinetic data following single dose administration of 6 mg tizanidine showed that younger subjects cleared the drug four times faster than the elderly subjects Tizanidine clearance is reduced by more than 50% in elderly patients with renal insufficiency (creatinine clearance < 25 mL/min) compared to healthy elderly subjects; this would be expected to lead to a longer duration of clinical effect.
The best muscle relaxant in the elderly cannot be determined from the provided information. Tizanidine and cyclobenzaprine have different pharmacokinetic profiles, but there is no direct comparison of their efficacy and safety in the elderly population.
- Tizanidine clearance is reduced in elderly patients with renal insufficiency, which may lead to a longer duration of clinical effect.
- Cyclobenzaprine has been studied in various clinical trials, but its efficacy and safety in the elderly population are not explicitly stated. Given the lack of direct information, no conclusion can be drawn about the best muscle relaxant in the elderly. 2 3
From the Research
Best Muscle Relaxant in Elderly
- The use of skeletal muscle relaxants in elderly patients is associated with an increased risk of injury, including falls and fractures 4, 5.
- A study found that the absolute increase in risk of injury in elderly patients using a skeletal muscle relaxant was small but statistically significant, with 333 patients needing to be treated to result in 1 additional injury 4.
- Carisoprodol, methocarbamol, and cyclobenzaprine were associated with an increased risk of injury in elderly patients 5.
- There is fair evidence that cyclobenzaprine, carisoprodol, and tizanidine are effective in treating musculoskeletal conditions, such as acute back or neck pain, but the evidence for their use in elderly patients is limited 6.
- Cyclobenzaprine has been evaluated in the most clinical trials and has consistently been found to be effective, but its use in elderly patients should be cautious due to the risk of adverse events 6, 7.
- The potential for abuse with carisoprodol is a concern, and its usefulness is mitigated by this risk 7.
- Metaxalone also appears to be effective, but there is limited data on its use in elderly patients 7.
- Baclofen and tizanidine are effective in treating spasticity, but their use in elderly patients should be cautious due to the risk of adverse events 8, 6.
- Dantrolene has been associated with rare serious hepatotoxicity and should be used with caution in elderly patients 6.