Activated charcoal is contraindicated in which of the following scenarios?

• A. Decreased level of consciousness
• B. Ingestion of caustic substances
• C. Inability to maintain airway
• D. All of the above

Answer: (D)

Activated charcoal works by adsorbing certain toxins in the GI tract to limit absorption, but its use requires a protected airway and a toxin for which charcoal is effective. If the patient cannot protect their airway (decreased level of consciousness or an inability to maintain airway), there is a real risk that the charcoal will be aspirated into the lungs, causing chemical pneumonitis or pneumonia. Ingestion of caustic substances is another contraindication because charcoal does not neutralize caustics and can complicate assessment or endoscopy of mucosal injuries, and it may not prevent damage from these substances. The same airway risk applies to someone who cannot reliably maintain their airway. Therefore, all of these scenarios are contraindications to using activated charcoal.