What is a recommended muscle relaxer for fibromyalgia?

Recommended Muscle Relaxer for Fibromyalgia

Traditional "muscle relaxants" like cyclobenzaprine, methocarbamol, carisoprodol, and metaxalone are not recommended as primary therapy for fibromyalgia because they do not directly relax skeletal muscle and lack evidence of efficacy in chronic pain, despite cyclobenzaprine showing some benefit for sleep rather than pain. 1, 2

Why Traditional Muscle Relaxants Are Not First-Line

The term "muscle relaxant" is misleading for fibromyalgia treatment because fibromyalgia involves central pain amplification, not actual muscle pathology. 1, 3 The drugs commonly called "muscle relaxants" (methocarbamol, carisoprodol, chlorzoxazone, metaxalone, cyclobenzaprine) have no evidence of efficacy in chronic pain and carry significant risks of adverse effects. 1

Cyclobenzaprine: The Exception with Caveats

If a "muscle relaxant" must be used, cyclobenzaprine is the only option with any supporting evidence, but it should be understood as primarily a sleep aid rather than a pain medication. 2

• Cyclobenzaprine received a "weak for" recommendation from the European League Against Rheumatism with only 75% agreement, indicating weak evidence. 2
• The Number Needed to Treat is 4.8 for patients to report themselves as "improved," but this improvement is primarily in sleep quality (SMD 0.34), not pain reduction. 2
• 85% of patients experienced side effects in clinical trials, and only 71% completed studies, indicating significant tolerability issues. 2
• A recent 2025 phase 3 trial showed bedtime sublingual cyclobenzaprine 5.6 mg improved pain scores (-1.8 vs -1.2 with placebo, P < 0.001), but this was a novel sublingual formulation specifically targeting nonrestorative sleep. 4

Dosing for cyclobenzaprine (if used): 10-40 mg daily at bedtime, though the sublingual formulation uses 5.6 mg. 2, 4

What Should Be Used Instead

For fibromyalgia, the evidence-based first-line pharmacological options are amitriptyline, duloxetine, or pregabalin—not traditional muscle relaxants. 3, 5

First-Line Medications (in order of preference):

1. Amitriptyline 10-50 mg at bedtime (start 10 mg, increase by 10 mg weekly to target 25-50 mg) - particularly beneficial for sleep disturbances with NNT of 4.1 for 50% pain relief. 3, 5

2. Duloxetine 60 mg once daily (start 30 mg for 1 week, then increase to 60 mg) - reduces pain, improves function, and treats comorbid depression. 3, 5

3. Pregabalin 300-450 mg/day in divided doses (start 75 mg twice daily, increase to 150 mg twice daily within 1 week) - reduces pain and improves sleep. 3, 5

Second-Line Option:

• Tramadol is recommended when first-line medications are ineffective, though it should be used with caution given opioid-related risks. 1, 5

Critical Pitfalls to Avoid

• Never prescribe corticosteroids or strong opioids for fibromyalgia—they lack efficacy and cause significant harm. 1, 3, 5
• Do not rely solely on pharmacological therapy. Non-pharmacological interventions (graduated exercise, cognitive behavioral therapy, heated pool therapy) have the strongest evidence and should be initiated first. 3, 5
• Avoid using NSAIDs as monotherapy—they show no benefit over placebo in fibromyalgia. 5
• In older adults (≥65 years), use caution with amitriptyline due to anticholinergic effects. 1, 5

The Bottom Line

If a patient specifically requests a "muscle relaxer," educate them that fibromyalgia is not a muscle disease but a central pain processing disorder. 3 The medications that actually work (amitriptyline, duloxetine, pregabalin) target central pain mechanisms, not peripheral muscle tension. 1, 3 Cyclobenzaprine may be considered as an adjunct for sleep disturbances, but it should never be the primary treatment strategy. 2