Baclofen is Primarily for Spasticity-Related Pain, Not General Pain Conditions
Baclofen is indicated specifically for pain associated with spasticity from multiple sclerosis and spinal cord pathology—it is NOT a general pain medication and should not be used for neuropathic pain, musculoskeletal pain, or rheumatic disorders. 1
FDA-Approved Indications
The FDA explicitly approves baclofen only for alleviating signs and symptoms of spasticity, particularly:
- Relief of flexor spasms and concomitant pain in multiple sclerosis 1
- Clonus and muscular rigidity associated with spasticity 1
- Spinal cord injuries and other spinal cord diseases 1
Critical caveat: Baclofen is NOT indicated for skeletal muscle spasm from rheumatic disorders, and its efficacy in stroke, cerebral palsy, and Parkinson's disease has not been established 1
Pain Mechanism Specificity
Baclofen's pain relief is mechanistically linked to its antispasticity effects:
- As a GABA-B agonist, it reduces spasticity-related pain by decreasing muscle tone and spasm frequency 2
- Intrathecal baclofen can suppress central dysesthetic pain in patients with spinal lesions, suggesting involvement of dysfunctional spinal GABA-B receptor systems 3
- It does NOT influence musculoskeletal pain or nociceptive pain from mechanical stimuli 3
When Baclofen Should NOT Be Used for Pain
Baclofen is NOT appropriate for:
- Neuropathic pain without spasticity—gabapentinoids (pregabalin, gabapentin) are first-line instead 4
- General musculoskeletal pain—consider duloxetine or TCAs 4
- Low back pain—only sparse data (2 trials) support its use 4
The American Geriatrics Society explicitly states there is minimal data supporting baclofen use for pain outside of spasticity-related conditions 4
Treatment Algorithm for Spasticity-Related Pain
First-line non-pharmacological approaches: 4, 5
- Antispastic positioning, range of motion exercises, stretching
- Splinting and serial casting
Pharmacological options when pain persists:
- Focal spasticity causing pain: Botulinum toxin is preferred over baclofen 4
- Generalized spasticity with pain: Oral baclofen 5-10 mg/day initially, titrating to 30-80 mg/day divided into 3-4 doses 4
- Severe refractory spasticity with pain: Intrathecal baclofen when >80% of patients show improvement in tone and >65% in spasms 2, 6
Important Safety Considerations
- Abrupt discontinuation can cause life-threatening withdrawal with seizures, hyperthermia, and rebound spasticity 2, 7
- May worsen obstructive sleep apnea by promoting upper airway collapse 4, 5
- Common adverse effects include sedation, weakness, vertigo, and psychological disturbances (10-75% incidence) 6
- Older adults rarely tolerate doses >30-40 mg/day 2