What is the recommended baclofen dosing and titration schedule for adults with spasticity, how should it be adjusted in moderate to severe renal impairment, and what are the dosing limits for children aged 12 years and older?

Baclofen Dosing for Adults with Spasticity

Begin oral baclofen at 5 mg three times daily (15 mg/day total) and increase by 5 mg per dose every 3 days, targeting a maintenance range of 40–80 mg/day divided three times daily, with mandatory dose reduction in renal impairment. 1

Standard Adult Dosing Protocol

• Initial dose: Start at 5 mg three times daily (total 15 mg/day) 1
• Titration schedule: Increase by 5 mg per dose every 3 days as tolerated 1
• Target maintenance dose: 40–80 mg/day divided into three daily doses 1
• Maximum dose: 80 mg/day is the usual maximum; higher doses markedly increase adverse effects without proportional benefit 1
• Dosing frequency: Three-times-daily administration is mandatory because baclofen has a short half-life and requires consistent plasma levels for continuous spasticity control 1

Critical Renal Dose Adjustments

Baclofen is primarily eliminated by renal excretion, making dose reduction essential in kidney disease. 2, 3, 4, 5

Moderate to Severe Renal Impairment

• CKD Stage 4 (eGFR 15-29 mL/min): Start with 7.5 mg daily total dose, divided into smaller doses 5
• CKD Stage 5 (non-dialysis, eGFR <15 mL/min): Start with 7.5 mg daily total dose 5
• Dialysis patients: Start with 2.5 mg daily total dose 5
• Minimum neurotoxic dose: As low as 10 mg daily in CKD stage 4-5, and 5 mg daily in dialysis patients 5

Renal Monitoring Considerations

• Baclofen blood levels can rise gradually over time even on stable dosing due to impaired renal clearance 3
• Patients with neurogenic bladder are at particular risk for renal insufficiency and require closer monitoring 3
• Low serum albumin independently increases risk of baclofen neurotoxicity (7.0% prevalence in severe CKD) 5
• Time-to-peak plasma levels and half-lives are substantially longer than standard references indicate, especially with renal impairment 3

Elderly Patient Adjustments

• Starting dose: Use the lower end of the range (5 mg three times daily) 1
• Titration interval: Slow to every 5–7 days instead of every 3 days 1
• Maximum tolerated dose: Typically 30–40 mg/day (lower than standard adults) 1
• Monitoring priorities: Muscle weakness, urinary dysfunction, cognitive changes, sedation, and fall risk 1

Pediatric Dosing (Age ≥12 Years)

• Titration rate: Daily dose increases of 5–15% once every 24 hours 6
• Slower and more conservative than adult titration to minimize adverse effects 6

Critical Withdrawal Prevention

Never discontinue baclofen abruptly—this is a life-threatening error. 1

• Tapering duration: Minimum of one week, preferably longer 1
• Withdrawal syndrome: Seizures, psychiatric symptoms, hyperthermia, hallucinations, and possible death 1
• Management: Symptoms usually respond to rapid baclofen re-introduction 1

Ongoing Safety Monitoring

Throughout treatment, assess regularly for:

• Muscle weakness (may worsen functional status) 1
• Urinary retention or incontinence 1
• Cognitive impairment and sedation 1
• Fall risk, especially in elderly patients 1

Drug Interaction Warning

• Avoid concurrent benzodiazepines in stroke recovery patients—the combination impairs neurological recovery and increases sedation 1
• Baclofen is a GABA-B agonist; combining with other CNS depressants compounds sedative effects 7, 4

When Oral Baclofen Fails

Intrathecal Baclofen Indications

• Consider for patients who do not respond to maximal oral doses (80 mg/day) 1
• Also indicated for intolerable oral side effects at therapeutic doses 1
• Success rate: More than 80% of appropriate candidates achieve meaningful improvement in muscle tone 1

Alternative Focal Treatments

• Botulinum toxin or phenol/alcohol injections for disabling or painful focal spasticity 1
• Neurosurgical options (selective dorsal rhizotomy, dorsal root entry zone lesions) reserved for refractory cases with acceptable operative risk 1

Common Pitfalls to Avoid

• Do not exceed 80 mg/day without compelling justification—adverse effects increase disproportionately 1
• Do not use twice-daily dosing—baclofen's short half-life requires three-times-daily administration 1
• Do not use standard doses in renal impairment—even 10 mg daily can cause neurotoxicity in CKD 5
• Do not stop abruptly—withdrawal can be fatal 1
• Do not assume muscle relaxants work by relieving muscle spasm—their effects are nonspecific, and baclofen is preferred when true spasm is suspected 7