Overview of the Decontamination Process of Charcoal

The use of activated charcoal for detoxifying or decontamination of stomach content, in instances of self or accidental poisoning, have been practiced for many decades. It is considered one of the mainstays of decontamination in acute poisoning while many different variations of its use, which should fit into many different patient states, are in existence.

How does charcoal act as a decontaminating agent?

The effect of decontamination made by charcoal is the result of its activation through treatment with oxygen. Thus, the actual decontamination agent is the ‘activated charcoal’ as against the usual charcoal that people see. Once treated, the charcoal which is made out of carbon will convert itself into a highly porous substance that increases its effective surface area to around 300 – 2000 square meters per gram. The porous nature of the activated charcoal allows air and fluids to flow through and therefore promote the toxic molecules to bind with the carbon surfaces of the activated charcoal.

With time and more binding, the activated charcoal could become saturated and therefore may have to be replaced as in the case of water filters.

What are the instances in which charcoal could not act as a decontamination agent?

Activated charcoal usually acts as an effective decontamination agent for most impurities although some do not respond well. These include alcohol, strong acids, strong alkali, metal drugs, gold, lithium, iron, potassium, mercury, ethanol, ethylene, dishwasher granules…etc.

What factors will contribute towards its effectiveness?

Among these factors, the pore size, the number and the distribution matters a lot towards its decontamination effect and these will depend mostly on the origin of its carbon and the manufacturing process. At the same time, the contact time between charcoal and the contaminant will also contribute towards its adsorption. When the pH value and the temperature go down, charcoal tends to act more effectively.

What are the other uses of charcoal apart from medicinal use?

The properties of charcoal have been used in many instances including air and water purification, soil detoxification as well as in the process of removing unwanted odors, toxins and flavors from foods.

How should the charcoal be used in managing oral poisonings?

The commonest method of giving charcoal is by swallowing although in unconscious patients, the oro-gastric or naso-gastric route can be used. Some health care providers may opt to do an aspiration of the stomach content before giving the activated charcoal.

Before giving the charcoal, the conscious patient will have a brief explanation of what is going to be done and in most circumstances the consent of the patient will be required. Furthermore, because of the poor palatability of charcoal taken alone, it may be accompanied by water or sorbitol. In some instances, there may be a need to repeat the treatment and in most circumstances, the usual dose of charcoal is around 1 gram per kilogram body weight.

What are the complications following giving charcoal?

Although most will tolerate the charcoal without any major issue, some would undergo intestinal obstruction as a result of concretion of the charcoal within the intestine. At the same time, the fluid shift resulting because of charcoal may require the patient to be on intravenous fluids during the therapy. Furthermore, introduction of charcoal may actually inhibit the absorption of certain drugs and therefore monitoring conditions which may become aggravated due to the absence of usual medication should also be important when treating with charcoal.