Baclofen

Administration

• Type: Muscle relaxant/anti-spasmodic
• Dosage Forms: tablet, intrathecal solution, preservative free intrathecal solution
• Dosage Strengths: tablet: 10, 20mg; intrathecal solution: 50, 500mcg/mL; preservative free intrathecal solution: 500, 1000, 2000 mcg/mL
• Routes of Administration: oral, intrathecal
• Common Trade Names: Lioresal, Gablofen

Adult Dosing

• 5-20mg PO 3-4 times/day
• maintenance intrathecal rate after titration: 22 to 1400 mcg/day

Pediatric Dosing

• 2-7yo: 10 to 15 mg/day PO in 2-3 divided doses, titrate to max 40mg/day in 3-4 divided doses
• >7 yo: 10 to 15 mg/day PO in 2-3 divided doses, titrate to max 60mg/day in 3-4 divided doses
• <12 yo: maintenance intrathecal rate after titration- 24 to 1199 mcg/day

Special Populations

• Pregnancy Rating: C
• Lactation risk: Infant risk minimal

Renal Dosing

• CrCl 50-80 mL/min: reduce dose by 1/3
• CrCl 30-50 mL/min: reduce dose by 1/2
• CrCl <30 mL/min: reduce dose by 2/3
• If HD, use intrathecal with caution, likely reduce dose

Hepatic Dosing

• No adjustment

Contraindications

• Allergy to class/drug

Adverse Reactions

Serious

• GI bleed
• Coma
• Seizure
• Aseptic meningitis
• Pneumonia
• Withdrawal

Common

• Hypotension
• Nausea/vomiting, constipation
• Dizziness, somnolence, asthenia, poor muscle tone
• Urinary complications

Pharmacology

• Half-life: 5 hours (oral), 1.5-4 hours (intrathecal)
• Metabolism: Hepatic (15%)
• Excretion: Mostly renal

Mechanism of Action

• GABA agonist

See Also

• Baclofen toxicity
• Baclofen withdrawal