What is the use of Beglofen (possibly related to Baclofen) in treating muscle spasticity?

Baclofen Use in Treating Muscle Spasticity

Baclofen is primarily indicated for treating spasticity resulting from multiple sclerosis and spinal cord injuries, where it effectively reduces muscle tone, flexor spasms, clonus, and muscular rigidity in patients with reversible spasticity. 1

Indications and Mechanism of Action

Baclofen is a GABA-B receptor agonist that works by:

• Normalizing altered interneurone activity
• Decreasing alpha motoneurone activity 2
• Reducing spastically increased muscle tone 2

FDA-Approved Indications:

• Spasticity from multiple sclerosis
• Spinal cord injuries and diseases 1

Not FDA-Approved For:

• Skeletal muscle spasm from rheumatic disorders
• Stroke (efficacy not established)
• Cerebral palsy (efficacy not established)
• Parkinson's disease (efficacy not established) 1

Efficacy

• In open-label studies of oral baclofen, the drug improved spasticity in 70-87% of patients
• Improvement in spasms was reported in 75-96% of patients 3
• Double-blind, placebo-controlled trials have shown statistically significant improvements in spasticity 3
• Comparable efficacy to tizanidine, though tizanidine may cause less weakness 3

Administration and Dosing

Oral Administration:

• Should be started with a low dose and gradually titrated up 4
• May cause significant sedation 4
• May have less impact on spasticity in stroke compared to other conditions 4

Intrathecal Administration:

• Reserved for patients unresponsive to maximum doses of oral baclofen, tizanidine, and/or dantrolene 3
• Delivers the drug directly into cerebrospinal fluid, bypassing the blood-brain barrier 5
• More effective at lower doses with fewer systemic side effects 5

• 80% of patients show improvement in muscle tone

• 65% of patients show improvement in spasms 3

Adverse Effects

Common Side Effects (10-75% of patients):

• Sedation or somnolence
• Excessive weakness
• Vertigo
• Psychological disturbances 3

Most adverse effects are:

• Not severe
• Dose-related
• Transient and/or reversible 3

Serious Risks:

• Withdrawal symptoms (seizures, psychic symptoms, hyperthermia) if abruptly discontinued 4, 3
• Higher risk in patients with renal disease 3
• Intrathecal overdose primarily from drug test doses or human error during pump refill 3

Comparative Treatments

For spasticity management, other options include:

1. Botulinum toxin: First-line for focal upper limb spasticity, reduces muscle tone without systemic side effects 4

2. Tizanidine: First-line oral medication for post-stroke spasticity, particularly effective for chronic stroke patients with spasticity and pain 4

3. Dantrolene: Consider when cognitive side effects must be minimized 4

4. Non-pharmacological interventions:

   • Functional electrical stimulation
   • Neuromuscular electrical stimulation
   • Transcutaneous electrical nerve stimulation
   • Positioning, passive stretching, and range-of-motion exercises 6, 4

Clinical Considerations

• Abrupt discontinuation must be avoided to prevent withdrawal complications 4
• Regular monitoring is essential for dose adjustments 7
• Focus treatment on improving function and relieving discomfort, not just reducing muscle tone 4
• Identify and treat factors that can worsen spasticity (skin pressure sores, fecal impaction, urinary tract infections) 4

Baclofen remains a valuable medication for spasticity management, particularly for spinal spasticity, with the benefit-risk assessment generally favorable when used appropriately 3.