Muscle Relaxants Are NOT Recommended as First-Line Therapy for Acute Musculoskeletal Pain
Based on the highest quality guideline evidence, you should NOT start with a muscle relaxant for acute non-spinal musculoskeletal pain. Instead, begin with topical NSAIDs with or without menthol gel as first-line therapy, followed by oral NSAIDs or acetaminophen if needed 1.
The Evidence Against Muscle Relaxants as First-Line
The 2020 ACP/AAFP guideline—the most authoritative source for this clinical scenario—makes no recommendation for muscle relaxants in their treatment algorithm for acute musculoskeletal injuries 1. This is a critical omission that speaks volumes: if muscle relaxants were effective first-line agents, they would have been included in these evidence-based recommendations.
The guideline explicitly prioritizes:
- First-line: Topical NSAIDs ± menthol (strong recommendation, moderate-certainty evidence)
- Second-line: Oral NSAIDs or oral acetaminophen (conditional recommendation, moderate-certainty evidence)
- Explicitly recommends AGAINST: Opioids including tramadol 1
Why This Matters
The most recent systematic review from 2025 examining non-benzodiazepine muscle relaxants for low back pain found that while these agents showed some benefit for pain relief (RR: 0.53), they were associated with significantly more adverse events (RR: 1.56), particularly central nervous system effects (RR: 2.40) 2. The evidence quality was only low-to-moderate certainty, and importantly, this was for low back pain—not the broader category of acute musculoskeletal injuries addressed in your question.
A 2026 systematic review using the REB method evaluated thiocolchicoside, methocarbamol, and diazepam specifically and found that none of these three commonly-used muscle relaxants demonstrated efficacy in acute low back pain 3. The studies were either at high risk of bias or showed no statistically significant benefit over placebo.
The Clinical Algorithm
Step 1: Start with topical NSAIDs (diclofenac, ketoprofen) with or without menthol gel applied to the affected area 1
Step 2: If topical therapy is insufficient or impractical, add oral NSAIDs (ibuprofen 400-600mg TID, naproxen 500mg BID) or oral acetaminophen 1000mg QID 1
Step 3: Consider acupressure or TENS for additional pain control if needed 1
Avoid: Muscle relaxants as routine first-line therapy given the lack of guideline support and unfavorable benefit-risk profile 2, 3
Important Caveats
- The combination of muscle relaxants with NSAIDs may provide marginally better global efficacy than NSAIDs alone (RR: 0.62), but this comes with increased CNS adverse effects (RR: 1.91) 2
- If you do consider a muscle relaxant after failing first-line therapy, the evidence suggests non-benzodiazepine agents are preferable to benzodiazepines, but expect sedation, dizziness, and CNS effects in your patient 2
- The older literature suggesting muscle relaxants as useful adjuvants 4, 5 predates the high-quality 2020 guideline and should not override current evidence-based recommendations
The bottom line: Topical NSAIDs are your starter medication, not muscle relaxants. The guideline evidence is clear, recent, and from the most prestigious sources in internal medicine and family practice 1.