What is the treatment for isolated elevated alcohols, specifically methanol or ethylene glycol poisoning?

Treatment of Isolated Elevated Alcohols: Methanol and Ethylene Glycol Poisoning

The treatment of methanol or ethylene glycol poisoning requires immediate administration of an alcohol dehydrogenase inhibitor (fomepizole preferred over ethanol) and hemodialysis for severe cases with significant metabolic acidosis, renal failure, or alcohol concentrations above 50 mg/dL.

Initial Assessment and Diagnosis

• Suspect toxic alcohol poisoning based on:
  • History of ingestion
  • Elevated anion gap metabolic acidosis
  • Increased osmolal gap
  • Visual disturbances (methanol)
  • Oxalate crystals in urine (ethylene glycol)
  • Documented serum concentration >20 mg/dL

Treatment Algorithm

1. Antidotal Therapy

• Fomepizole (preferred first-line) 1:

  • Loading dose: 15 mg/kg IV over 30 minutes
  • Maintenance: 10 mg/kg every 12 hours for 4 doses
  • Then 15 mg/kg every 12 hours until:
    • Alcohol levels <20 mg/dL
    • Patient asymptomatic with normal pH

• Ethanol (alternative if fomepizole unavailable) 2:

  • Less predictable efficacy
  • Requires more intensive monitoring
  • Associated with CNS depression and dysphoria

2. Extracorporeal Treatment (ECTR)

Indications for hemodialysis 3:

• When fomepizole is used:

  • Alcohol concentration >50 mmol/L (>310 mg/dL)
  • Osmol gap >50
  • Glycolate concentration >12 mmol/L
  • Anion gap >27 mmol/L

• When ethanol is used:

  • Alcohol concentration >50 mmol/L (>310 mg/dL) (strong recommendation)
  • Alcohol concentration 20-50 mmol/L (124-310 mg/dL) (suggested)
  • Osmol gap >50 (strong recommendation)
  • Osmol gap 20-50 (suggested)

• When no antidote is available:

  • Alcohol concentration >10 mmol/L (>62 mg/dL)
  • Osmol gap >10

• Clinical indications (regardless of antidote):

  • Coma
  • Seizures
  • Acute kidney injury (KDIGO stage 2 or 3)
  • Chronic kidney disease (eGFR <45 mL/min/1.73m²)

3. Hemodialysis Modality

• Intermittent hemodialysis is strongly preferred over other ECTR modalities 3, 4
• If intermittent hemodialysis unavailable, use continuous kidney replacement therapy
• Use high-flux membranes for more efficient toxin removal 5

4. Adjustment of Fomepizole Dosing During Hemodialysis 1

• Increase frequency to every 4 hours during hemodialysis
• After hemodialysis completion:
  • If <1 hour since last dose: no additional dose
  • If 1-3 hours: administer half of next scheduled dose
  • If >3 hours: administer next scheduled dose

5. Criteria for Discontinuing ECTR 3, 4

• Anion gap <18 mmol/L (strong recommendation)
• Alcohol concentration <4 mmol/L (25 mg/dL) (suggested)
• Correction of acid-base abnormalities (suggested)

Special Considerations

• Do not base treatment solely on reported ingested dose 3
• Activated charcoal is ineffective for these poisonings 4
• Supportive care should include:
  • IV fluids
  • Correction of electrolyte abnormalities
  • Management of metabolic acidosis
  • Monitoring for hypoglycemia (especially with methanol)

Common Pitfalls to Avoid

1. Delayed treatment - Begin antidotal therapy immediately upon suspicion, don't wait for confirmatory levels
2. Inadequate monitoring - Follow both alcohol levels and acid-base status
3. Underestimating severity - The parent compounds are relatively non-toxic; toxicity comes from metabolites 2
4. Using polycarbonate syringes/needles with fomepizole - Can compromise the integrity of equipment 1
5. Premature discontinuation of hemodialysis - Continue until meeting specific cessation criteria
6. Failure to adjust fomepizole dosing during hemodialysis - The drug is dialyzable and requires more frequent administration

Early recognition and aggressive treatment with appropriate antidotes and hemodialysis when indicated significantly reduce morbidity and mortality in these potentially life-threatening poisonings.