Is baclofen (GABA receptor agonist) safe for treating muscle spasms?

Baclofen Safety for Muscle Spasms

Baclofen is safe and effective for treating muscle spasticity resulting from multiple sclerosis, spinal cord injuries, and other spinal cord diseases, but it is not indicated for skeletal muscle spasm from rheumatic disorders or for spasticity in stroke, cerebral palsy, or Parkinson's disease. 1

Indications and Efficacy

• Baclofen is primarily indicated for the alleviation of signs and symptoms of spasticity resulting from multiple sclerosis, particularly for relief of flexor spasms, concomitant pain, clonus, and muscular rigidity 1
• Baclofen may also be of value in patients with spinal cord injuries and other spinal cord diseases 1
• Studies show baclofen is effective in reducing spasticity of spinal origin in approximately 80% of patients and reducing the number and severity of spasms in 87% of patients 2
• Baclofen is not indicated for treatment of skeletal muscle spasm resulting from rheumatic disorders 1
• The efficacy of baclofen in stroke, cerebral palsy, and Parkinson's disease has not been established and is therefore not recommended for these conditions 1

Safety Considerations and Side Effects

• Common adverse effects include drowsiness, light-headedness, dizziness, sedation, shortness of breath, nausea, vomiting, and abdominal pain 3
• Baclofen should be used with caution when spasticity is utilized to sustain upright posture and balance in locomotion 1
• The central nervous system effects of baclofen may be additive to those of alcohol and other CNS depressants 1
• Side effects necessitating dosage reduction occur in approximately 20% of patients 2
• In patients with epilepsy, the clinical state and electroencephalogram should be monitored regularly, as deterioration in seizure control has been reported 1
• Rare neurologic side effects include muscular dyskinesia, particularly when baclofen treatment is first initiated 4

Administration and Dosing

• For oral administration, the Society for Perioperative Assessment and Quality Improvement (SPAQI) recommends taking baclofen preoperatively including the day of operation 3
• Typical dosing range for oral baclofen is 30-80 mg/day, divided into 3-4 doses 5
• For patients with severe spasticity who don't respond to oral baclofen, intrathecal baclofen may be considered 5, 6
• Intrathecal baclofen delivers the medication directly into the cerebrospinal fluid, bypassing the blood-brain barrier and optimizing efficacy while minimizing side effects 7

Special Populations

• Safety and effectiveness in pediatric patients below the age of 12 years have not been established 1
• A dose-related increase in ovarian cysts has been observed in female patients treated with baclofen 1
• Baclofen should be used with caution in patients with obstructive sleep apnea as it may worsen the condition by promoting upper airway collapse during sleep 5

Withdrawal Considerations

• Significant withdrawal symptoms have been reported following abrupt discontinuation of baclofen in patients who take it long-term 3
• Withdrawal symptoms include visual and auditory hallucinations, anxiety, agitation, delirium, fever, tremors, tachycardia, and seizures 3
• Abrupt withdrawal of intrathecal baclofen is potentially life-threatening, with symptoms including high fever, altered mental status, rebound spasticity, and muscle rigidity that can lead to rhabdomyolysis, multiorgan failure, and death 3

Treatment Alternatives

• For spasticity management, first-line approaches include antispastic positioning, range of motion exercises, stretching, splinting, and serial casting 5
• Botulinum toxin may be more effective than baclofen for certain applications of focal spasticity 5, 8
• For neuropathic pain, gabapentinoids (pregabalin, gabapentin) have stronger evidence for efficacy 5
• For musculoskeletal pain, consider analgesic antidepressants, particularly duloxetine and TCAs 5