Treatment of swallowed poisons has usually involved some method to remove as much toxic material as possible from the gastrointestinal tract either by inducing vomiting or through the use of gastric lavage. For many years, attempts were also made to find "antidotes" for commonly ingested materials. These would be given orally in the hope that they would convert the toxic material to a non-toxic form or neutralize it. Unfortunately, many of these treatments were more toxic than the original poison swallowed. One exception is the use of activated charcoal.

In an 1830 demonstration before the French Academy of Science, a French pharmacist ingested a fatal amount of strychnine along with 15 grams of activated charcoal. He survived the ingestion, developing no symptoms at all, but failed to impress the academy sufficiently to gain widespread use of activated charcoal in treating poison.Charcoal is a black, tasteless, odorless, insoluble powder that is completely inert and is the product of organic vegetable matter, usually wood pulp, when burned at high temperatures. It has many uses: an absorbent to remove impurities (e.g., home water purification systems and a filtering agent in fish tanks). The charcoal used to treat swallowed poisons, however, is substantially different.

"Activation" occurs when charcoal is exposed to steam and strong acids, which creates tiny pores on each particle of charcoal. This network of pores increases the surface area enormously. With this extremely large surface area, activated charcoal will bind many commonly ingested toxic materials. Although physically similar to scrapings of burnt toast or barbecue-style charcoal, activated charcoal is extremely different and the two cannot be used interchangeably.

Using activated charcoal

Activated charcoal should be diluted with water and given as a slurry of soup-like consistency. This slurry may be drunk if the victim is cooperative and the airway is intact. The palatability of the black, gritty charcoal has been said to be a major drawback of this therapy, especially in children. Many people have attempted to improve the taste or consistency by adding chocolate syrup, sherbet, ice cream, milk and other flavoring agents, but most of these flavorings substantially decrease the binding capacity of the charcoal and should not be used.

Actually, the biggest drawback to the acceptance of charcoal is its appearance. Placing the charcoal slurry in a container that is opaque and having the victim ingest it through a straw greatly helps its ingestion.

Using ipecac and activated charcoal at the same time is discouraged. When activated charcoal is given before ipecac, the charcoal will bind the ipecac and may prevent the induction of vomiting. When given after ipecac, victims may vomit the charcoal and increase their risk of inhalation into the lungs. Recent studies comparing vomiting, lavage and activated charcoal have shown that activated charcoal is superior to these other gastric-emptying procedures.

Advantages of activated charcoal

Activated charcoal is inexpensive, safe, and an effective means for decreasing drug absorption. Its use has become standard emergency department poisoning treatment.

Some people advocate its in-home use as early as possible. Unfortunately, it has been shown that parents have difficulty giving the charcoal to children in the home setting and less-than-effective amounts are often given. Therefore, at this time, it is generally not recommended to use activated charcoal in the home.

Activated charcoal can be useful for lengthy transportation times.

- Alton Thygerson is a professor of health sciences at Brigham Young University.