Naproxen vs Baclofen for Inflammatory Conditions with Muscle Spasm
For an adult patient with inflammatory conditions and potential muscle spasm, naproxen is the preferred treatment over baclofen. Naproxen directly addresses inflammation and pain, while baclofen is primarily indicated for spasticity (not simple muscle spasm) and lacks evidence for inflammatory conditions 1, 2.
Treatment Algorithm
First-Line: Naproxen
- Naproxen is effective for inflammatory rheumatic diseases, acute musculoskeletal pain, and various pain states with well-established efficacy comparable to other NSAIDs 3, 4.
- The drug provides both analgesic and anti-inflammatory effects through its NSAID mechanism 3.
- Dosing is convenient at once or twice daily, with a well-established safety profile over many years of clinical use 3, 4.
- For acute low back pain with muscle spasm, naproxen alone demonstrated significant efficacy in controlled trials 5.
When Baclofen is NOT Appropriate
- Baclofen is a GABA-B agonist indicated specifically for spasticity (sustained muscle contraction from upper motor neuron lesions), not for simple muscle spasm or inflammatory pain 2.
- There is minimal data supporting baclofen use for pain outside spasticity-related conditions 2.
- Muscle relaxants like baclofen do not actually relax tense skeletal muscles in humans—their mechanism remains unclear and may relate only to sedative properties 6, 7.
- Baclofen causes significant adverse effects including dizziness, gastrointestinal symptoms, sedation, and excessive weakness in 25-75% of patients 8, 9.
When to Consider Adding a Muscle Relaxant
If naproxen alone provides insufficient relief for acute muscle spasm:
- Consider cyclobenzaprine (NOT baclofen) at 5 mg three times daily for 7-14 days maximum 6.
- Combination therapy with cyclobenzaprine plus naproxen showed greater reduction in objective muscle spasm and tenderness compared to naproxen alone, though with increased drowsiness 5.
- This approach is only for acute musculoskeletal pain with true muscle spasm, not chronic conditions 6.
Critical Safety Considerations
Naproxen Precautions
- Assess cardiovascular and gastrointestinal risk factors before prescribing, as NSAIDs carry risks for myocardial infarction and GI bleeding 1.
- Use the lowest effective dose for the shortest duration necessary 1.
- Consider co-administration with a proton-pump inhibitor in higher-risk patients 1.
- Contraindications include active GI bleeding, severe renal failure, and uncontrolled hypertension 1.
Baclofen Risks (if mistakenly prescribed)
- Abrupt cessation can cause life-threatening withdrawal syndrome with high fever, altered mental status, and severe rebound spasticity 2.
- May worsen obstructive sleep apnea by promoting upper airway collapse 2.
- Can cause respiratory depression, particularly concerning in patients with compromised respiratory function 2.
- Contraindicated in significant hepatic dysfunction 2.
Common Pitfalls to Avoid
- Do not prescribe baclofen for simple muscle spasm or inflammatory pain—it is only indicated for spasticity from neurological conditions like stroke, spinal cord injury, or multiple sclerosis 2, 8, 9.
- Do not use muscle relaxants for chronic pain conditions—there is no evidence of benefit 6.
- Avoid the misconception that "muscle relaxants" actually relax muscles; their effects are nonspecific and primarily sedative 6, 7.
- In older adults, avoid muscle relaxants entirely due to fall risk and anticholinergic effects 6.
When Baclofen IS Appropriate
Baclofen should only be considered for:
- Spasticity from upper motor neuron lesions (stroke, spinal cord injury, multiple sclerosis, cerebral palsy) 2, 8, 9.
- Patients who have failed first-line non-pharmacological approaches (positioning, range of motion exercises, stretching, splinting) 2.
- Starting dose of 5-10 mg/day, titrated slowly to 30-80 mg/day divided into 3-4 doses 2.
- Intrathecal baclofen is reserved for severe refractory spasticity unresponsive to maximum oral doses, with >80% improvement in muscle tone 2, 8.