An antidote to killer alcohols

When a 24-year-old tourist ingested a large quantity of ethylene glycol (anti-freeze) recently, the story made the headlines. The only treatment available was alcohol. The woman was given three standard drinks (as vodka) every hour for three days at Mackay Base Hospital. This was to avoid the toxic effects of ethylene glycol metabolites which otherwise would have been responsible for serious toxicity including metabolic acidosis, blindness, cardiovascular instability, potential renal failure and death.

“Using alcohol as an antidote is not risk-free and requires experience,” explained toxicologist Professor Andrew Dawson of the NSW Poisons Information Centre.

Fomepizole is a drug used as an antidote in confirmed or suspected methanol or ethylene glycol (such as antifreeze) poisoning. Fomepizole has recently received regulatory approval in Australia after being approved for many years overseas.

“There are two forms of alcohol — methanol and ethylene glycol — that once they are consumed produce toxic metabolites that are potentially fatal,” said Professor Dawson.

“That’s why the approval for fomepizole is so welcome,” he said. “Fomepizole is a competitive inhibitor of alcohol dehydrogenase, which catalyses the initial steps in the metabolism of ethylene glycol and methanol to their toxic metabolites. It’s much more straightforward and reliable to use. Fomepizole will make toxic alcohol ingestion less complicated to manage, especially in centres not currently very well equipped to manage such cases.”

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