Which poison is not typically treated with activated charcoal: alcohol, methanol, aspirin, or ethylene glycol?

Alcohol is the Poison Not Treated with Activated Charcoal

Alcohol (ethanol) is the poison that cannot be effectively treated with activated charcoal, unlike aspirin, methanol, and ethylene glycol.

Why Activated Charcoal Doesn't Work for Alcohol

Activated charcoal works by binding to toxins in the gastrointestinal tract, preventing their absorption. However, it has specific limitations:

• According to guidelines, activated charcoal is ineffective for poisoning with alcohols, along with acids, bases, organic solvents, inorganic salts, metals, iron, lithium, and potassium 1.

• Research confirms that oral activated charcoal does not significantly impair ethanol absorption. A study of healthy adults showed that pre-treatment with activated charcoal (60g) before ethanol ingestion did not reduce the fraction of ethanol absorbed 2.

Effective Treatments for Different Toxic Alcohols

For Ethanol (Drinking Alcohol)

• Supportive care is the mainstay of treatment
• No specific antidote is typically required
• Activated charcoal is ineffective

For Methanol and Ethylene Glycol

These toxic alcohols require different management approaches:

1. Antidotes:

   • Fomepizole (preferred) or ethanol to block alcohol dehydrogenase (ADH) 3, 4
   • Prevents formation of toxic metabolites

2. Extracorporeal Treatment:

   • Hemodialysis is a key element in severe poisoning 5, 3
   • Removes both parent compounds and toxic metabolites

3. Supportive Care:

   • IV fluids
   • Correction of electrolyte abnormalities
   • Management of acidemia

For Aspirin (Salicylate) Poisoning

• Activated charcoal is highly effective when administered within 1 hour of ingestion 1
• May be effective up to 4-6 hours for extended-release formulations

Clinical Considerations

• Toxic alcohols (methanol and ethylene glycol) are metabolized to more toxic substances by alcohol dehydrogenase, making early intervention crucial 6

• The EXTRIP workgroup recommends extracorporeal treatment for ethylene glycol poisoning based on specific criteria including ethylene glycol concentration, osmol gap, and presence of metabolic acidosis 5

• When treating toxic alcohol poisonings, fomepizole has largely replaced ethanol as the antidote of choice in recent years 4

Key Takeaway

While activated charcoal is an important first-line treatment for many poisonings including aspirin, it has no role in managing alcohol (ethanol) poisoning. The other substances listed in the question (methanol, aspirin, and ethylene glycol) all have some evidence supporting activated charcoal use, though methanol and ethylene glycol primarily require antidotal therapy and potentially hemodialysis for severe cases.