How is antifreeze poisoning treated?

• A. Ethanol (20%) competitive inhibitor of alcohol dehydrogenase.
• B. Vitamin K.
• C. Activated charcoal.
• D. Sodium bicarbonate therapy.

Answer: (A)

Blocking the formation of toxic metabolites is the key idea in treating ethylene glycol (antifreeze) poisoning. Ethylene glycol is metabolized by alcohol dehydrogenase into glycolic and oxalic acids, which cause severe metabolic acidosis and renal injury. Administering ethanol provides a competing substrate for the enzyme, effectively occupying alcohol dehydrogenase and slowing or stopping the conversion of ethylene glycol to those harmful metabolites. This gives the body time to eliminate ethylene glycol and reduces toxic effects. If available, fomepizole would be even more specific, but ethanol is the classic antidotal approach because it competitively inhibits the same enzyme. Supportive measures like correcting acidosis may be used, while activated charcoal has limited value once ethylene glycol is absorbed, and vitamin K is unrelated to this poisoning.