Activated Charcoal Revisited

Activated charcoal (AC) is used in clinical toxicology to prevent the systemic absorption of toxic agents from the gastrointestinal tract and to enhance the elimination of toxic agents already absorbed. Single oral doses of AC decrease the absorption of most drugs as well as organic and inorganic materials with the exception of ethanol, strong acids and alkalis, iron, and lithium. The efficacy of AC is inversely related to the time elapsed after the ingestion of toxic substances. Activated charcoal should probably be given soon after most significant ingestions because of the low frequency of serious complications and the absence of effective techniques to enhance the elimination of most toxins once absorbed. The administration of multiple doses of activated charcoal has been shown to enhance the elimination of a variety of drugs. Although shortening the half-life of a drug in overdose should logically benefit a patient clinically, the proof of this is still lacking. Therefore, administration of multiple doses of activated charcoal should mainly be considered when confronted with possible life-threatening intoxications with carbamazepine, dapsone, phenobarbital, quinine, or theophylline.