Treatment of Baclofen Toxicity
The treatment of baclofen toxicity requires immediate supportive care in a monitored setting, with airway management and mechanical ventilation for respiratory depression being the primary interventions for severe cases. 1, 2
Clinical Presentation of Baclofen Toxicity
Baclofen toxicity presents with a spectrum of symptoms depending on the ingested dose:
Central Nervous System:
- Altered consciousness (ranging from drowsiness to deep coma)
- Hyporeflexia
- Seizures (tonic-clonic)
- Respiratory depression requiring mechanical ventilation
Cardiovascular System:
- Bradycardia
- Hypertension
- Cardiac conduction abnormalities (premature ventricular contractions)
Other:
- Hypothermia
- Autonomic disturbances
- Psychotic symptoms
Management Algorithm for Baclofen Toxicity
1. Initial Assessment and Stabilization
- Airway management: Secure airway and provide mechanical ventilation for respiratory depression
- Vital sign monitoring: Continuous monitoring of heart rate, blood pressure, temperature
- Laboratory evaluation: Obtain baclofen levels if available (levels >0.5 μg/mL correlate with severe symptoms)
2. Acute Oral Baclofen Overdose
- Gastrointestinal decontamination: Single dose of activated charcoal if presentation is within 1-2 hours of ingestion 3
- Supportive care:
- Mechanical ventilation for respiratory depression
- Treatment of seizures with benzodiazepines or antiepileptics
- Management of bradycardia and hypotension as needed
- Temperature regulation for hypothermia
3. Intrathecal Baclofen (ITB) Overdose
- Immediate cessation of baclofen delivery through the pump system 2
- CSF aspiration to reduce baclofen load in severe cases
- Intensive care monitoring with supportive treatment
4. Intrathecal Baclofen Withdrawal
- Restore ITB delivery as soon as possible 4
- Alternative treatments if ITB cannot be immediately restored:
- High-dose oral baclofen (though acute withdrawal may still occur)
- Intravenous benzodiazepines (short-acting preferred)
- Low-dose propofol in selected cases 2
Monitoring and Prognosis
- Patients who have taken a single dose of baclofen ≥200 mg should be managed in centers able to provide continuous monitoring of life functions 1
- Those with higher doses (>500 mg) should be hospitalized in a Toxicology Unit or Intensive Care Unit with mechanical ventilation capabilities 1
- Baclofen levels obtained approximately 14 hours after ingestion show a linear correlation with length of mechanical ventilation needed 3
- Despite severe presentation, prognosis can be good with appropriate supportive care, even in cases of profound coma mimicking brain death 5
Special Considerations
- For patients on long-term baclofen therapy, abrupt discontinuation can lead to potentially life-threatening withdrawal syndrome including high fever, altered mental status, rebound spasticity, and muscle rigidity 4
- Withdrawal can progress to rhabdomyolysis, multiorgan failure, and death if not promptly recognized and treated 4
- Intrathecal clonidine withdrawal (often used with baclofen) can result in hypertensive crisis and cardiomyopathy 4
Pitfalls to Avoid
- Failure to recognize baclofen toxicity as it can mimic brain death 5
- Delayed intubation in patients with deteriorating consciousness
- Use of physostigmine and flumazenil is generally not advised in baclofen toxicity 6
- Premature discontinuation of monitoring, as symptoms may persist despite non-detectable baclofen levels 3
The management of baclofen toxicity requires prompt recognition and aggressive supportive care. With appropriate treatment, even severe cases can have good outcomes.