What is the recommended dosage and treatment protocol for baclofen in managing muscle spasticity?

Baclofen Dosage and Treatment Protocol for Muscle Spasticity

For muscle spasticity management, oral baclofen should be initiated at 5 mg three times daily and gradually titrated to an effective dose of 30-80 mg/day divided into 3-4 doses, with intrathecal baclofen reserved for severe cases unresponsive to oral therapy. 1, 2

Treatment Algorithm for Spasticity Management

First-Line Non-Pharmacological Approaches

• Begin with antispastic positioning, range of motion exercises, stretching, splinting, and serial casting 3, 1
• Physical modalities such as neuromuscular electrical stimulation (NMES) or vibration may temporarily improve spasticity as adjuncts to rehabilitation therapy 3

Pharmacological Management

• Oral Baclofen Administration:

  • Initial dose: 5 mg three times daily 1, 2
  • Gradually increase by 5 mg per dose every 3 days as tolerated 1
  • Effective dosage range: 30-80 mg/day divided into 3-4 doses 1
  • Older adults rarely tolerate doses greater than 30-40 mg per day 2
  • Monitor for side effects including sedation, weakness, vertigo, and psychological disturbances 4

• Alternative Oral Agents:

  • Tizanidine: Starting dose 2 mg up to three times daily 2
  • Dantrolene: Consider for generalized spasticity 1
  • Avoid diazepam and other benzodiazepines during stroke recovery due to potential negative effects on recovery 3, 1

For Focal Spasticity

• Targeted injection of botulinum toxin is recommended over oral medications 3, 1
• Botulinum toxin has been shown to be superior to oral baclofen for certain applications, particularly ankle spasticity 1, 5

For Severe Spasticity Unresponsive to Oral Medications

• Intrathecal Baclofen Therapy:

  • Consider for chronic stroke patients with spasticity resulting in pain, poor skin hygiene, or decreased function 3
  • Indicated for patients unresponsive to maximum doses of oral medications 1, 4
  • Studies show >80% of patients have improvement in muscle tone and >65% have improvement in spasms with intrathecal baclofen 1, 4
  • Can be considered as early as 3-6 months after stroke for patients refractory to other treatments 3

• Last Resort Options:

  • Neurosurgical procedures such as selective dorsal rhizotomy or dorsal root entry zone lesion may be considered 3, 1

Important Precautions and Monitoring

• Avoid abrupt discontinuation of baclofen as it can cause severe withdrawal symptoms including seizures, psychic symptoms, and hyperthermia 4
• Baclofen blood levels may rise gradually over time in some patients on a stable dosing regimen, particularly those with impaired renal function 6
• Use with caution in patients with renal disease as administration may carry an unnecessarily high risk 4
• Monitor for muscle weakness, urinary function changes, cognitive effects, and sedation 2
• Baclofen may worsen obstructive sleep apnea by promoting upper airway collapse during sleep 1, 5

Mechanism of Action and Efficacy

• Baclofen is a GABAB agonist that reduces spasticity by normalizing altered interneurone activity and decreasing alpha motoneurone activity 7
• In open-label studies, oral baclofen improved spasticity in 70-87% of patients and spasms in 75-96% of patients 4
• The pharmacokinetics of high-dose baclofen may include longer time-to-peak plasma levels and plasma half-lives than previously reported 6
• Baclofen reduces spastically increased muscle tone and Babinski sign but has limited effect on muscle force, tendon reflexes, and ankle clonus 7