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Toxicology

Baclofen Toxicity

Baclofen is a centrally acting muscle relaxant used to manage spasticity associated with various neurologic conditions, including multiple sclerosis, cerebral palsy, and spinal cord injury. Baclofen toxicity may result from overdose, accumulation in renal impairment, or withdrawal of intrathecal therapy and can be life-threatening. Clinical manifestations range from somnolence, hypotonia, and respiratory depression to seizures, coma, and cardiovascular instability. Diagnosis is primarily clinica

v1 · Reviewed Nov 7, 2026 by Automated Clinical Reviewer (Strict Verbatim v1)
  • Baclofen toxicity may result from overdose, accumulation in renal impairment, or withdrawal of intrathecal therapy and can be life-threatening.
  • Clinical manifestations range from somnolence, hypotonia, and respiratory depression to seizures, coma, and cardiovascular instability.
  • Baclofen toxicity can be life-threatening.
  • Serious toxicity may occur with oral doses greater than 200 mg.
  • Baclofen poisoning may present with confusion, respiratory depression, seizures, and paralysis.
  • Severe baclofen poisoning may mimic brain death.
  • Most serious toxic effects are associated with doses greater than 200 mg.
  • Diagnosis is primarily clinical and supported by medication history.
  • Initial evaluation of baclofen toxicity should prioritize airway, breathing, and circulation, with supportive care provided as needed to stabilize the patient.
  • A detailed history should be obtained after stabilization.
  • History should determine whether baclofen exposure resulted from intentional ingestion, necessitating suicidality assessment, or an inadvertent medication error.
  • Neurologic examination should include assessment of mental status, pupillary response, reflexes, muscle tone, and clonus.
  • Hypotonia and flaccid paralysis are suggestive of baclofen toxicity.
  • Cardiovascular toxicity may present with 1st-degree heart block, prolonged QTc interval, premature atrial contractions, or supraventricular tachycardia on electrocardiography (ECG).
  • Laboratory studies should be obtained after completion of a thorough history and physical examination.
  • Bedside blood glucose measurement should be performed promptly in patients presenting with altered mental status.
  • Additional laboratory evaluation should include a basic metabolic panel to assess electrolyte abnormalities and renal function.
  • Salicylate and acetaminophen concentrations should be obtained in cases of suspected intentional ingestion or suicidality to evaluate for possible coingestion.
  • Additional diagnostic evaluation should include ECG to assess for cardiac arrhythmias and computed tomography of the head to exclude alternative causes of altered mental status.
  • In comatose patients, electroencephalography (EEG) may assist in identifying nonconvulsive status epilepticus.
  • The pump should be interrogated when intrathecal delivery is involved, with prompt communication to the managing physician.
  • Obtaining vital signs
  • Assessing cardiac conduction abnormalities with ECG and continuous cardiac monitoring
  • Evaluating airway, breathing, and circulation, with close monitoring for respiratory depression and profound CNS depression
  • Obtaining laboratory studies and imaging as clinically indicated
  • Considering EEG in patients requiring mechanical ventilation or experiencing seizures
Serum baclofen concentration
Toxic plasma concentrations following oral baclofen ingestion are reported at 1.1 to 3.5 mg/L. Plasma concentrations are not useful in intrathecal baclofen exposure due to limited BBB penetration.
  • Management consists of supportive care, airway protection, seizure control, and hemodialysis in selected cases.
  • Treatment of baclofen toxicity is primarily supportive.
  • Stabilization of airway, breathing, and circulation is the priority.
  • Endotracheal intubation and mechanical ventilation is indicated in the presence of respiratory depression or profound CNS depression.
  • Intravenous fluids may be used initially for hypotension, though vasopressor support may be required for refractory cases.
  • Seizures are managed with benzodiazepine administration.
  • Activated charcoal may be given for gastrointestinal decontamination early after ingestion, typically within 2 hours, if the patient is alert and able to protect the airway.
  • Activated charcoal is contraindicated in the presence of CNS depression, vomiting, or seizures due to aspiration risk.
  • Hemodialysis may be used to enhance drug elimination, particularly in patients with underlying renal impairment.
  • The EXtracorporeal Treatments in Poisoning (EXTRIP) workgroup recommends intermittent hemodialysis in baclofen toxicity with concomitant renal dysfunction in patients presenting with coma requiring mechanical ventilation.
  • All symptomatic and intentional baclofen overdoses warrant hospital admission.
  • Patients experiencing hemodynamic instability or significant CNS depression should be admitted to the intensive care unit.
  • Baclofen should be withheld until clinical improvement of toxicity is confirmed.
  • Reinitiation of the medication is important after resolution of toxicity to prevent withdrawal, which may be severe.
  • Providing endotracheal intubation and mechanical ventilation when warranted
  • Initiating cardiovascular support with intravenous fluids and vasopressors as needed
  • Administering benzodiazepines for seizure control
  • Contacting poison control or a medical toxicologist for guidance
  • Consulting nephrology for possible hemodialysis when recommended by toxicology or poison control services
  • Consulting intensivists for intensive care unit admission and ongoing critical care monitoring
  • Patients with intrathecal pumps should be treated at facilities with clinicians experienced in pump management.
  • The recommended approach for a suspected pump malfunction causing overdose is to deactivate the pump and replace the reservoir with saline.
  • CSF removal via lumbar puncture may be considered in severe cases to reduce drug concentration.
  • Pump reactivation should occur within 48 hours of discontinuation to prevent baclofen withdrawal.
  • Baclofen toxicity may mimic multiple alternative etiologies, including sedative-hypnotic overdose, opioid overdose, severe metabolic encephalopathy, and status epilepticus, which may contribute to delayed recognition.
  • Additional differential diagnoses include sepsis, meningitis, encephalitis, stroke, intracranial hemorrhage, and hypoglycemia.
  • Suspected intentional overdose warrants psychiatric consultation for comprehensive evaluation and management.
  • Potential complications include aspiration, prolonged encephalopathy, rhabdomyolysis, and death.
  • Complications of baclofen toxicity are often secondary to severe CNS and respiratory depression.
  • Anoxic brain injury, aspiration pneumonia, pressure ulcers, rhabdomyolysis, and hypothermia may be observed after prolonged periods without medical intervention.
  • Patients should be monitored for baclofen withdrawal in the setting of chronic use.
  • Evaluation of the etiology of the overdose is necessary after return to baseline mental status.
  • If overdose is related to pump malfunction, the appropriate specialty team should be notified and the pump addressed prior to baclofen reinitiation.
  • review
    Baclofen Toxicity. StatPearls [Internet] — Emily K. Kershner, Madison Bompard, Richard J. Chen — StatPearls Publishing, 2026

Decision support only. Verify against local protocols and current labeling. Source: www.ncbi.nlm.nih.gov