Toxic Alcohol Ingestion - Methanol

Author: Michelle Lin, MD
Updated: 6/15/2012

Toxic Alcohol Ingestion: Methanol

General concepts for all 3 toxic alcohols:

  • Parent compounds (not metabolites) cause high osmolal gap
  • When NAD depleted, pyruvate converts to lactate - which then causes lactic acidosis
  • See metabolism of alcohols diagram below

Methanol: Factoids

Solvent found in cleaning and printing solutions, adhesives, stains, paint removers, antifreeze agent in windshield wiping fluid, camp stove fuel, gasoline additive


  • Peak serum concentration 30-60 minutes, elimination half-life 12-20 hours
  • Permanent blindness reported at as little as 0.1 mL/kg (6-10 mL in adults)
  • Lethal dose = 1-2 mL/kg
  • Metabolite (eg. formic acid) causes toxicity, but does NOT cause osmolal gap

Classic Presentation

Classic Profile

  • Altered mental status
  • Visual disturbances
  • Abdominal pain
  • High anion gap metabolic acidosis
  • High osmolal gap

Signs and Symptoms

  • CNS: Headache, lethargy, confusion, Parkinsonian extrapyramidal symptoms
  • Ocular: Blurry vision, central scotoma, impaired pupillary response, photophobia, retinal edema (permanent damage in 25-33% of patients)
  • GI: Vomiting, abdominal pain, pancreatitis

Stages of Presentation

Stage Clinical findings
Early Mild euphoria, inebriation, drowsiness
Latent (lasting 6-30 hours) Normal sensorium but blurred vision
Late Severe systemic toxicity with worsening acidosis


Goal: Prevent further formation of formic acid (using fomepizole) and eliminate toxic metabolites (through dialysis)

  • Folic or folinic acid supplementation to enhance formate metabolism
  • Antidote: Fomipezole inhibits alcohol dehydrogenase (alternative = ethanol)
Fomipezole Dosing
Loading dose 15 mg/kg IV
Maintenance dose 10 mg/kg IV every 12 hours x 2 days

American Academy of Clinical Toxicology guidelines

Suspected or confirmed methanol clinical pathway

Metabolism of alcohols

Metabolism of alcohols diagram


  • Jammalamadaka D, Raissi S. Ethylene glycol, methanol and isopropyl alcohol intoxication. Am J Med Sci. 2010 Mar;339(3):276-81. doi: 10.1097/MAJ.0b013e3181c94601. [PubMed]
  • Kraut JA, Kurtz I. Toxic alcohol ingestions: clinical features, diagnosis, and management. Clin J Am Soc Nephrol. 2008 Jan;3(1):208-25. Epub 2007 Nov 28. [PubMed]
  • Marraffa JM, Cohen V, Howland MA. Antidotes for toxicological emergencies: a practical review. Am J Health Syst Pharm. 2012 Feb 1;69(3):199-212. doi: 10.2146/ajhp110014 [PubMed]
  • Barceloux DG, Bond GR, Krenzelok EP, Cooper H, Vale JA; American Academy of Clinical Toxicology Ad Hoc Committee on the Treatment Guidelines for Methanol Poisoning. American Academy of Clinical Toxicology practice guidelines on the treatment of methanol poisoning. J Toxicol Clin Toxicol. 2002;40(4):415-46. [PubMed]