Activated charcoal (medication)
Activated charcoal, or activated carbon, is used as a medication to treat poisonings following excessive oral ingestion of certain medications or poisons. Side effects may include aspiration into the lungs.
While it is used for many toxic ingestion, there is not good evidence that it improves outcomes. It is not effective for a number of poisonings including: strong acids or bases, iron, lithium, arsenic, methanol, ethanol or ethylene glycol.
Tablets or capsules of activated carbon are used in many countries as an over-the-counter drug to treat diarrhea, indigestion, and flatulence. There is some evidence of its effectiveness to prevent diarrhea in cancer patients who have received irinotecan. It can interfere with the absorption of some medications, and lead to unreliable readings in medical tests such as the guaiac card test. Activated carbon is also used for bowel preparation by reducing intestinal gas content before abdominal radiography to visualize bile and pancreatic and renal stones. A type of charcoal biscuit has also been marketed as a pet care product.
Incorrect application (e.g. into the lungs) results in pulmonary aspiration which can sometimes be fatal if immediate medical treatment is not initiated. The use of activated carbon is contraindicated when the ingested substance is an acid, an alkali, or a petroleum product.
Mechanism of action
It is thought[by whom?] to bind the poison and prevent its absorption by the gastrointestinal tract. In cases of suspected poisoning, medical personnel administer activated carbon on the scene or at a hospital's emergency department. In rare situations activated carbon is used in Intensive Care to filter out harmful drugs from the blood stream of poisoned patients. Activated carbon has become the treatment of choice for many poisonings, and other decontamination methods such as ipecac-induced emesis or stomach pumping are now used rarely.
While activated carbon is useful in acute poisoning, it has been shown to not be effective in long term accumulation of toxins, such as with the use of toxic herbicides.
Mechanisms of action:
- Binding of the toxin to prevent stomach and intestinal absorption. Binding is reversible so a cathartic such as sorbitol may be added as well.
- It interrupts the enterohepatic and enteroenteric circulation of some drugs/toxins and their metabolites.
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