Management overview for methanol and ethylene glycol poisonings

This monograph discusses the management of poisonings due to the toxic alcohols, methanol and ethylene glycol.

For management of poisoning from the toxic alcohol, isopropyl alcohol (eg from hand sanitisers or disinfectants), see Isopropyl alcohol poisoning.

Poisonings by other toxic alcohols (eg diethylene glycol, polyethylene glycol, triethylene glycol) are rare and information on their metabolism, pathophysiology and risk assessment is limited. For poisonings due to these and other toxic alcohols, consult a clinical toxicologist.

For the management of ethanol intoxication, see Ethanol intoxication.

In Australia, methylated spirits does not contain methanol and pure methanol can only be purchased by laboratory or industrial suppliers. Other sources of methanol include model aeroplane fuel, rocket fuel, and racing car fuel, which also contains nitromethane. Methanol poisoning sometimes occurs in clusters associated with poorly distilled alcohol.

Ethylene glycol and other glycols are found in coolants, antifreeze, brake fluids and some solvents.

Because of potentially severe and irreversible complications from methanol (visual loss) and ethylene glycol (kidney failure), discuss these poisonings urgently with a clinical toxicologist or poisons information centre (13 11 26).

Treatment for methanol or ethylene glycol poisoning involves antidotal therapy with ethanol or fomepizole. Antidotal therapy inhibits alcohol dehydrogenase, thereby preventing ongoing metabolism of the parent alcohol to its toxic acid metabolites (formic acid for methanol; glycolic acid, glyoxylic acid and oxalic acid for ethylene glycol). These metabolites cause metabolic acidosis and are responsible for most of the systemic effects of poisoning. Antidotal therapy can be kidney- or vision-saving. Haemodialysis may also be indicated to rapidly remove methanol or ethylene glycol and their toxic acid metabolites. Corticosteroids may be indicated as adjunctive therapy in methanol poisoning to prevent irreversible visual impairment and blindness.

Co-ingestion of ethanol with methanol or ethylene glycol is protective against toxicity, and occurs when a patient ingests a mixture of ethanol and methanol (eg traditional methylated spirits). This may delay the onset of methanol toxicity until the ethanol has been metabolised.