Activated charcoal is a form of carbon that has been treated to open up millions of microscopic pores, making it extremely porous. Through this activation process, it can have a huge surface area of anywhere between 300 – 2000 square metres per gram. It is this high surface area and porosity that make activated charcoal a useful tool in industry and medicine, for its valued ability to soak up undesirable material. It is particularly useful and effective in medicine.
Why activated charcoal is useful in medicine
Before the use of activated charcoal became widespread, a crude variation consisting of carbonised wood was used by the ancient Egyptians to treat cases of poisoning and for purification purposes. Activated carbon was first produced in its modern form during the 19th century, revolutionising industry and medicine.
When a person ingests a toxic substance, there is only a small window of opportunity to treat them with gastric lavage or a substance like ipecac that induces vomiting. After about 30 minutes, most of the remaining poison that hasn’t been absorbed already has moved into the intestines, and can not be cleared with these conventional methods. Activated charcoal is not only non-toxic, but can pass through the body completely undigested, and thus is an effective way to remove poisonous substances from both the stomach and intestines.
How activated charcoal is used
Activated charcoal is generally used as soon as possible when a case of poisoning is presented, and may sometimes be used as a secondary treatment directly after gastric lavage is performed. A dose of around 50 grams, depending on weight and other factors, is given orally if possible, and consists of a slurry of charcoal and sorbitol. The sorbitol acts as a laxative to aid and speed passage through he bowels in order to remove the poison as quickly as possible and avoid constipation.
If a patient is unable to take the activated charcoal orally due to palatability issues or unconsciousness, it can also be administered by intubation through either the nose or mouth. In the case of an unconscious patient, an endotracheal tube is used to allow the patient to receive oxygen whilst the dose is given, preventing vomiting and the associated risk of choking.
Depending on the type of poison, a doctor may decide to give a smaller dose every couple of hours, as in the case of long-acting medicines. Blood levels of the poison are monitored and if the charcoal isn’t working well enough, the patient may be indicated for kidney dialysis to remove the poison from the blood stream.
When activated charcoal should not be used
Not every type of poison can be adsorbed by activated charcoal, and toxins like alcohol can’t be treated effectively this way. It should not be given in the case of a patient who has swallowed highly acidic or basic chemicals, has an obstruction of the intestines, or in the case that an available antidote is more appropriate for treating the poisoning. This is the case with drugs like opiates that can be treated extremely effectively with an opiate antagonist such as naloxone.
Activated charcoal is an effective remedy for accidental and suicidal poisoning, but it does have its limits and contraindications and should only be administered by a doctor or licensed health professional familiar with its use. This ensures that the activated charcoal can be used appropriately and for the intended benefits with less risk of side effects.
