Baclofen Contraindications
Baclofen is absolutely contraindicated in patients with hypersensitivity to baclofen and should be avoided in patients with severely reduced kidney function (eGFR <30 mL/min/1.73m²) or those on renal replacement therapy. 1, 2
Primary Contraindications
- Hypersensitivity to baclofen - The only absolute contraindication listed in the FDA label 1
- Severe renal impairment - Baclofen is primarily excreted via the kidneys; patients with eGFR <30 mL/min/1.73m² are at high risk for toxicity 2
- End-stage kidney disease/dialysis - Can lead to neurotoxicity and hemodynamic instability 2
Relative Contraindications and Cautions
Renal Function Considerations
- Moderate renal impairment (eGFR 30-60 mL/min/1.73m²) - Requires dose reduction to prevent toxicity 2
- Monitoring - Patients with any degree of renal impairment should be closely monitored for signs of toxicity
Neurological Considerations
- Seizure disorders - Abrupt discontinuation can precipitate seizures 3
- Cognitive impairment - May worsen confusion in vulnerable patients 4
- Concurrent benzodiazepine use - Can exacerbate baclofen neurotoxicity with marked depression of consciousness and respiration 4
Special Populations
- Elderly patients - Higher risk of adverse effects including confusion, sedation, and falls 5
- Patients with unrealistic goals - Relative contraindication for intrathecal baclofen therapy 6
- Patients with unmanageable mental health issues - May affect compliance with intrathecal baclofen therapy 6
Baclofen Toxicity Signs and Management
Signs of Toxicity
- Neurotoxicity (confusion, encephalopathy)
- Hemodynamic instability
- Multifocal myoclonus
- Respiratory depression (especially with concurrent benzodiazepines)
- EEG abnormalities including generalized slowing and triphasic waves 4
Management of Toxicity
- Discontinuation of baclofen
- Supportive care
- Hemodialysis may be effective in reversing toxicity in severe cases 2
- Avoid benzodiazepines in patients with suspected baclofen toxicity 4
Withdrawal Considerations
Abrupt discontinuation of baclofen, especially after prolonged use, can lead to serious withdrawal symptoms including:
Always taper baclofen gradually when discontinuing treatment after prolonged use to prevent withdrawal syndrome 5, 7.
Clinical Context for Use
Despite these contraindications, baclofen remains an important GABA-B agonist used for:
- Spasticity of spinal origin 7
- Trigeminal neuralgia (limited evidence) 5
- Regurgitation or belch-predominant GERD symptoms 5, 8
When appropriately prescribed with consideration of contraindications, baclofen can be an effective treatment option for these conditions.