Activated charcoal is contraindicated in which scenario?

• A. Altered mental status with alkali ingestion
• B. Ingestion of water
• C. Ingestion of sugar
• D. Ingestion of fat

Answer: (A)

Activated charcoal is used to bind many oral toxins in the GI tract, but it has clear limits. It should not be given when the patient cannot protect their airway, because vomiting and decreased consciousness greatly raise the risk of charcoal being aspirated into the lungs, leading to serious pulmonary injury. It is also contraindicated with caustic (alkali) ingestions, since these substances can cause severe tissue damage and charcoal does not prevent that injury; it may even complicate evaluation and care. So, in a patient with altered mental status and alkali ingestion, activated charcoal should not be used.

Ingestion of non-toxic liquids like water or sugary substances isn’t an indication for charcoal, and hydrocarbons like fats are not ideal for charcoal use either due to poor binding and aspiration risk. The key idea is airway protection and the caustic nature of the substance.