Activated Charcoal: A Selective Tool
Activated charcoal was once a routine treatment for nearly all ingestion poisonings in EMS. However, evidence has shown that its benefits are limited to specific situations, and its risks (aspiration, vomiting, intestinal obstruction) must be carefully weighed. Modern prehospital protocols use activated charcoal selectively, typically with online medical control authorization.
How Activated Charcoal Works
Activated charcoal is a fine black powder with an enormous surface area created by processing carbon at high temperatures. When ingested, it adsorbs (binds to its surface) many toxic substances in the gastrointestinal tract, preventing their absorption into the bloodstream. One gram of activated charcoal has a surface area of approximately 1,000 square meters, allowing it to bind significant quantities of toxins.
When Activated Charcoal May Be Beneficial
Activated charcoal is most effective when administered within 1 hour of a potentially toxic ingestion. Its benefit decreases rapidly after this window. Consider activated charcoal when:
- The ingestion occurred within the past 1 hour (some protocols allow up to 2 hours)
- The substance ingested is known to be adsorbed by charcoal
- The patient is alert, oriented, and able to protect their airway
- The patient is not at risk for vomiting or aspiration
- The ingestion is potentially life-threatening
- Medical control authorizes administration
Contraindications
- Altered mental status or inability to protect the airway
- Ingestion of corrosives (acids or alkalis) where charcoal may obscure endoscopic evaluation
- Ingestion of hydrocarbons (aspiration risk outweighs benefit)
- Substances not adsorbed by charcoal: iron, lithium, potassium, alcohols, heavy metals
- Risk of vomiting with potential for aspiration
- Patients who may need endoscopy
Dosing and Administration
The standard adult dose is 1 g/kg (typically 50 to 100 grams) mixed with water into a slurry. Pediatric dosing is 1 g/kg. Administer orally; do not administer through a nasogastric tube in the prehospital setting unless specifically authorized by medical control and the patient's airway is secured. Encourage the patient to drink the entire dose, though palatability is a significant challenge. Some products are premixed with a sweetener to improve taste.