Introduction
Activated charcoal, or activated carbon, is an amorphous form of carbon prepared from incomplete combustion of carbonaceous organic matter. It is activated by an oxidizing gas flow at high temperature passed over its surface to make a fine network of pores, producing a material with large surface area and high affinity for various substances. It is used as a gastric decontaminant and emergency medication to treat poisonings following excessive oral ingestion of certain medications or poisons by absorbing most drugs and toxins. However its effects is rendered poor on some compounds including strong acids or bases, methanol and substances with limited absorptive capacity (including iron, lithium, arsenic). It works by binding to the poison in the gastric contents in a reversible fashion thus may be adminstered together with a cathartic to reduce the small intestine transit time. The clinical applications of activated charcoal occured in the early 1800's. While this management for acute poisoning is considered fairly invasive, it is on the World Health Organization's List of Essential Medicines that includes the most important medications needed in a basic health system.
Uses
Activated charcoal is a gastric decontamination agent used in emergency clinical settings as a antidote to treat poisonings following excessive oral ingestion of certain medications or poisons.
Used as a antidote to treat poisonings following excessive oral ingestion of certain medications or poisons.
Associated Conditions
Pharmacodynamics
Activated charcoal is used as a gastric decontamination agent in emergency clinical settings in case of poison or medication overdose. Studies show that early administration of one dose of activated charcoal can adsorb poison in the stomach and reduce absorption while it also works long after ingestion, by interruption of enterohepatic and enterovascular cycling of poison.
Mechanism of Action
Active charcoal acts by binding to the pharmaceutical drugs or poisons such as organophosphates and decreasing the systemic absorption of toxic agents. Molecules with large volume of distribution, thus likely having higher lipid solubility, tends to bind have better absorptive binding to activated charcoal. Following the administration of activated charcoal, cathartics are indicated to evacuate the charcoal-poison bonded complex from the gastrointestinal tract. Activated charcoal may also have an effect on systemic drug levels by lowering the serum levels of already absorbed drugs or toxins. Many absorbed drugs that undergo significant hepatic metabolism and conjugation are eliminated via bile into the small intestines. When they reach the small intestines, drug conjugates can undergo hydrolysis and return to the enterohepatic circulation. Activated charcoal interferes with this process and binds to the conjugated drug before hydrolysis or the free deconjugated drug before reabsorption.
Absorption
No evidence of systemic absorption of activated charcoal
Route of Elimination
Fecal excretion.
Toxicity
Adverse effects from the treatment include aspiration into the lungs and possibly pneumonitis, black stools, vomiting, and constipation or diarrhea. The oral LD50 value in rats is 15400mg/kg.
Food Interactions
- Take with or without food. Give a higher dose of activated charcoal if it is administered after a large meal.
Dosage
- Adult: 2-4 tab tds-qds.
- Children: ½ adult dose.
- Adult: 2-4 tab/kg body weight
- children: 3-4 tab/kg body weight
- Adult: Disintegrate 1-2 tab. Repeat every 2 hr.
