Treatment of Baclofen Overdose: Strategies for Effective Care

Baclofen is a muscle relaxant commonly prescribed for spasticity, but excessive doses can lead to serious toxicity. Overdose cases may result from accidental ingestion, intentional misuse, or impaired drug clearance in individuals with kidney dysfunction. Prompt recognition and intervention are crucial to prevent life-threatening complications.

Recognizing Toxic Dosages

Determining toxic thresholds is complex, as susceptibility varies based on renal function, concurrent medications, and overall health. Therapeutic doses range from 5 to 20 mg per dose, with a maximum daily intake of 80 mg. Toxicity has been reported at doses as low as 100 mg, while some individuals tolerate higher amounts before severe symptoms appear. A study in Clinical Toxicology found that ingestion above 200 mg significantly increases the risk of central nervous system depression, respiratory compromise, and hemodynamic instability.

Renal impairment is a key factor in baclofen accumulation, as the drug is primarily excreted through the kidneys. Patients with chronic kidney disease (CKD) or acute kidney injury (AKI) may experience toxicity even at standard doses due to reduced clearance. Research in Nephrology Dialysis Transplantation highlights cases of profound sedation and respiratory depression in CKD patients receiving doses considered safe for those with normal kidney function. This underscores the need for dose adjustments in individuals with renal impairment.

Pediatric and geriatric populations face heightened risk due to differences in metabolism and sensitivity to central nervous system depressants. Accidental ingestion in children, even at doses as low as 20–30 mg, has triggered seizures and coma, as documented in Pediatrics. In older adults, reduced hepatic and renal clearance, combined with polypharmacy, increases the likelihood of adverse effects. Clinicians must carefully titrate doses and monitor for early signs of overdose.

Key Warning Signs

Baclofen overdose manifests through neurological, respiratory, and cardiovascular symptoms, with severity depending on the dose and individual response. As a gamma-aminobutyric acid (GABA) agonist, baclofen suppresses neuronal excitability, often leading to drowsiness, confusion, and disorientation, which can progress to stupor or coma. A retrospective analysis in Neurology found nearly 70% of overdose patients had Glasgow Coma Scale (GCS) scores below 8, indicating severe impairment. This CNS depression can mimic opioid toxicity or hypoglycemia, making thorough clinical assessment essential.

Respiratory depression is another hallmark of toxicity, particularly in individuals who ingest large quantities or have renal impairment. Baclofen’s inhibitory effects on brainstem respiratory centers can cause bradypnea, hypoventilation, and, in extreme cases, respiratory arrest. A Chest case series reported that nearly 40% of overdose patients required mechanical ventilation. The risk is higher in those with preexisting pulmonary conditions or concurrent sedative use. Early recognition of shallow breathing, decreased respiratory rate, and hypoxia is critical.

Cardiovascular instability may also occur, though less frequently than CNS and respiratory effects. Patients can experience bradycardia and hypotension due to autonomic suppression, while some exhibit paradoxical hypertension and tachycardia due to compensatory sympathetic activation. A study in The American Journal of Emergency Medicine found that 15% of overdose cases presented with hemodynamic fluctuations requiring intervention. Continuous blood pressure and heart rate monitoring is necessary to manage potential instability.

Immediate Stabilization

Managing baclofen overdose begins with securing the airway, breathing, and circulation, as rapid neurological and respiratory deterioration can occur. Patients with significant CNS depression may lose protective reflexes, increasing aspiration risk. Endotracheal intubation is often required for those with a GCS score below 8 or respiratory insufficiency. Mechanical ventilation may be necessary in cases of profound respiratory depression, with continuous pulse oximetry and arterial blood gas analysis guiding ventilatory support.

Cardiovascular monitoring is essential. Intravenous crystalloid fluids are the first-line treatment for hypotension, while vasopressors such as norepinephrine are used in refractory cases. Patients experiencing paradoxical hypertension require cautious antihypertensive management to avoid excessive drops in perfusion pressure. Electrocardiographic monitoring helps detect arrhythmias, which, though rare, have been documented in severe cases.

Gastrointestinal decontamination may help if the overdose is recognized early. Activated charcoal, when given within one hour of ingestion, can reduce systemic absorption. Gastric lavage is rarely indicated but may be considered in massive overdoses. Since baclofen is primarily cleared by the kidneys, forced diuresis is ineffective. However, hemodialysis has successfully removed the drug in patients with renal impairment, with case reports in Nephrology describing significant clinical improvement following dialysis.

Pharmacologic Approaches

No specific antidote exists for baclofen overdose, so treatment focuses on symptom control. Naloxone has been explored due to its efficacy in opioid overdoses, but its effectiveness in baclofen toxicity is inconsistent. Some case reports suggest partial improvement in mental status, though controlled studies have not confirmed a reliable benefit. This likely stems from baclofen’s distinct mechanism as a GABA_B receptor agonist.

Benzodiazepines are used to manage baclofen-induced seizures and agitation, particularly in pediatric cases. Lorazepam or diazepam helps suppress hyperexcitability, though excessive dosing may worsen respiratory depression. In refractory cases, barbiturates such as phenobarbital may be used, though they require intensive care monitoring due to prolonged sedation risk.

Preventive Measures

Reducing baclofen overdose risk requires careful prescribing, patient education, and monitoring strategies. Clinicians must assess patient-specific factors before initiating treatment. Individuals with renal impairment require dose adjustments due to baclofen’s primary renal excretion. Conservative dosing and extended intervals help prevent drug accumulation. Caution is also necessary when prescribing baclofen alongside other CNS depressants, such as opioids or benzodiazepines, which increase the risk of respiratory suppression.

Patient education is crucial in preventing unintentional and intentional overdoses. Clear guidance on dosing schedules, side effects, and toxicity signs can help patients recognize when medical intervention is needed. Patients and caregivers should be informed that excessive drowsiness, confusion, or breathing difficulties warrant immediate attention. In households with children, securing medications in child-resistant containers and storing them out of reach can prevent accidental ingestion. Pharmacists can reinforce safety measures by providing verbal counseling and written instructions during prescription dispensing.