What is the management approach for toxic alcohol ingestion?

Management of Toxic Alcohol Ingestion

Fomepizole is the preferred first-line antidote for toxic alcohol poisoning, with ethanol as an acceptable alternative when fomepizole is unavailable. 1, 2

Initial Assessment and Management

• Immediately begin treatment upon suspicion of toxic alcohol ingestion based on patient history, anion gap metabolic acidosis, increased osmolar gap, visual disturbances, or oxalate crystals in urine 2
• Assess for metabolic acidosis by checking anion gap, with values >27 mmol/L indicating severe poisoning 3
• Evaluate for neurological symptoms, including altered mental status, seizures, or coma, which may appear early in poisoning 3
• Check for signs of acute kidney injury, a common complication of glycol poisoning 3

Antidotal Therapy

• Administer fomepizole as the preferred antidote to block alcohol dehydrogenase (ADH), preventing formation of toxic metabolites 1, 2
• Fomepizole dosing regimen:
  • Loading dose: 15 mg/kg IV infused over 30 minutes 2
  • Maintenance: 10 mg/kg every 12 hours for 4 doses, then 15 mg/kg every 12 hours 2
  • Continue until toxic alcohol concentrations are <20 mg/dL and patient is asymptomatic with normal pH 2
• If fomepizole is unavailable, ethanol may be used as an alternative ADH inhibitor, though it is less preferred due to:
  • Need for compounding in pharmacy 1
  • Increased risk of medication errors 1
  • Need for intensive monitoring 4
  • Potential sedative effects 4

Hemodialysis Considerations

• Initiate hemodialysis in addition to ADH blockade for patients with: 2, 4
  • Renal failure 2
  • Significant or worsening metabolic acidosis 2
  • Toxic alcohol concentration ≥50 mg/dL 2
• During hemodialysis, adjust fomepizole dosing to every 4 hours due to its dialyzability 2
• Continue hemodialysis until toxic alcohol concentrations are <20 mg/dL and metabolic abnormalities are corrected 2

Monitoring and Supportive Care

• Frequently monitor both toxic alcohol concentrations and acid-base balance using serum electrolytes (anion gap) and/or arterial blood gas analysis 2
• Consider thiamine and pyridoxine as adjuvant therapy to support recovery, particularly in patients with suspected alcohol use disorder 3
• Provide supportive care for organ dysfunction, particularly renal support if acute kidney injury develops 3
• Monitor for alcohol withdrawal in patients with alcohol use disorder, especially during hemodialysis 3

Treatment Discontinuation

• Treatment with fomepizole may be discontinued when: 2
  • Toxic alcohol concentrations are undetectable or <20 mg/dL 2
  • Patient is asymptomatic with normal pH 2

Special Considerations

• Do not use polycarbonate syringes or polycarbonate-containing needles when administering fomepizole 2
• Dilute fomepizole in at least 100 mL of sterile 0.9% sodium chloride or 5% dextrose solution 2
• Fomepizole may solidify at temperatures below 25°C (77°F); if this occurs, liquefy by running the vial under warm water or holding in hand 2
• Patients treated with fomepizole before onset of significant acidosis may not require hemodialysis, particularly in ethylene glycol poisoning 4

Clinical Outcomes

• Early administration of fomepizole has been shown to prevent renal injury in ethylene glycol poisoning 4
• In a systematic review, mortality rates for methanol poisoning were 17.1% with fomepizole versus 21.8% with ethanol; for ethylene glycol poisoning, mortality rates were 4.1% with fomepizole versus 18.1% with ethanol 5
• All patients require immediate treatment as toxic alcohol poisoning can lead to accumulation of toxic metabolites causing metabolic acidosis, seizures, coma, and death if left untreated 2, 6