Pharmacology. Activated charcoal, by virtue of its large surface area, adsorbs many drugs and toxins. Highly ionic salts (eg, iron, lithium, and cyanide) and small polar molecules (eg, alcohols) are poorly adsorbed. Repeated oral doses of activated charcoal can increase the rate of elimination of some drugs that have a small volume of distribution and that undergo enterogastric or enterohepatic recirculation (eg, digitoxin) or diffuse into the GI lumen from the intestinal circulation (eg, phenobarbital and theophylline). See also discussion in Section I. Co-administration with cathartics is of unproven benefit and is associated with risks (see Cathartics).

Indications

1. 
   

   Activated charcoal is often used orally after an ingestion to limit drug or toxin absorption. It is most effective if given within 1 hour of an ingestion, and effectiveness is subject to numerous variables (eg, charcoal-to-substance ratio, contact time, pH, substance solubility, and whether ingested drug is likely to persist in the stomach or upper small intestine). However, evidence for benefit in the clinical setting is limited.

   
   
2. 
   

   Repeated doses of activated charcoal may be indicated to enhance elimination of some drugs if (1) more rapid elimination will benefit the patient and (2) more aggressive means of removal (eg, hemodialysis) are not immediately indicated or available (See Repeat-dose activated charcoal).

   
   
3. 
   

   Repeated doses of activated charcoal may be useful when the quantity of drug or toxin ingested is greater than one-tenth of the usual charcoal dose (eg, an aspirin ingestion of >6–10 g) or when surface contact with the drug is hindered (eg, pharmacobezoars and wrapped or packaged drugs).

Contraindications

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