What is the approved (intended) indication of baclofen (extended‑release) for treating chronic upper and mid‑back muscle pain in a middle‑aged patient with full‑body stiffness, tachycardia, erectile dysfunction, insomnia, and melasma?

Baclofen's Intended Use for Muscle Pain

Baclofen is FDA-approved specifically for spasticity from spinal cord injury and multiple sclerosis—not for chronic musculoskeletal back pain—and there is only sparse evidence (2 trials) supporting its efficacy for low back pain. 1

FDA-Approved Indications

Baclofen's intended uses are narrowly defined:

• Spasticity from spinal cord lesions (traumatic injury, multiple sclerosis, other spinal pathologies) 2, 3, 4
• Intrathecal baclofen for severe spasticity unresponsive to maximum oral doses 2, 4

The drug works as a GABA-B agonist to reduce velocity-dependent muscle tone and involuntary spasms characteristic of upper motor neuron syndromes. 5, 3

Why Baclofen Is NOT Indicated for Your Type of Pain

Your upper and mid-back muscle pain represents chronic musculoskeletal pain, not spasticity. The American College of Physicians and American Pain Society explicitly state there is "little evidence for the efficacy of baclofen" for low back pain, with only 2 sparse trials available. 1

Key distinctions:

• Spasticity = velocity-dependent increased muscle tone from CNS injury (stroke, spinal cord damage, MS) 5, 4
• Musculoskeletal pain = chronic pain from muscle strain, myofascial dysfunction, or mechanical causes 1

Baclofen does not directly relax skeletal muscle and has no evidence of efficacy in chronic pain conditions. 5, 6

Why Baclofen Appeared to Help You

Your response to baclofen ER 20mg twice daily likely represents:

1. Off-label sedative/CNS depressant effects rather than true antispasticity action 1
2. Placebo response or coincidental improvement 1
3. Nonspecific muscle relaxation from CNS depression, not targeted spasticity reduction 5

The American Geriatrics Society notes that most muscle relaxants "do not directly relax skeletal muscle and have no evidence of efficacy in chronic pain." 5

Critical Safety Concerns for Your Situation

You are now at risk for severe withdrawal syndrome if baclofen is stopped abruptly. 5, 6, 3

Withdrawal symptoms include:

• Seizures, hallucinations, delirium 6
• High fever, tachycardia (which you already experience) 6, 3
• Rebound muscle rigidity 6
• Potentially life-threatening complications 3, 4

Baclofen must be tapered slowly over weeks if discontinuation is necessary. 5, 6

What You Should Do Instead

For chronic musculoskeletal back pain, the evidence supports:

1. Gabapentinoids (pregabalin 150-300mg or gabapentin) as first-line for neuropathic components 5, 6

   • You already tried pregabalin 150-225mg without relief, suggesting your pain may not be primarily neuropathic

2. Tricyclic antidepressants for chronic pain relief 1

   • Duloxetine or amitriptyline have stronger evidence than baclofen for chronic back pain 6

3. Non-pharmacologic approaches (physical therapy, acupuncture, cognitive-behavioral therapy) 1

4. Short-term NSAIDs or acetaminophen for acute flares 1

Common Pitfalls to Avoid

• Do not continue baclofen long-term for non-spasticity pain—you are using it off-label without evidence and risking dependence 1, 5
• Do not stop baclofen abruptly—taper slowly under physician supervision 5, 6, 3
• Do not assume tizanidine failed—2mg at night is a subtherapeutic dose; therapeutic dosing is 2mg three times daily, titrated to 8-36mg/day 5
• Recognize that your systemic symptoms (tachycardia, erectile dysfunction, insomnia) may indicate an underlying condition (anxiety, autonomic dysfunction, hormonal issues) that requires separate evaluation 1

Bottom Line

Baclofen is intended for spasticity from spinal cord injury or MS, not chronic musculoskeletal back pain. 1, 2, 4 Your relief from baclofen represents off-label use without supporting evidence, and you now face withdrawal risks if discontinued. Work with your physician to slowly taper baclofen while transitioning to evidence-based treatments for chronic musculoskeletal pain (tricyclic antidepressants, duloxetine, or non-pharmacologic therapies). 1, 5