Activated charcoal is used for certain oral poisonings within 1 hour; what are key contraindications?

• A. For certain oral poisonings within 1 hour; contraindications include caustics, hydrocarbons, and when airway protection is not assured
• B. For any poisoning at any time
• C. For inhaled poisons only
• D. Only for metals

Answer: (A)

Activated charcoal works by binding many organic toxins in the gastrointestinal tract to prevent their absorption, so it’s most useful when given promptly after ingestion. The key is that it is not appropriate for every poisoning and must be given only when the airway can be protected and the toxin is likely to be adsorbed. The major contraindications you need to recognize are caustic substances (strong acids or alkalis) because contact with charcoal can worsen local injury and these poisons aren’t effectively adsorbed; hydrocarbons (like gasoline or kerosene) because they carry a high risk of aspiration and charcoal does not reliably adsorb them; and any situation where the patient cannot maintain a protected airway (unconsciousness or poor gag reflex) since charcoal can be aspirated into the lungs and cause a chemical pneumonitis.

That’s why this treatment isn’t used for all poisonings, nor for inhaled poisons or metals, and why timing and airway status are essential considerations in deciding whether to administer activated charcoal.