Use of Activated Charcoal in Drug Overdose

Desiree Lie, MD, MSEd

Disclosures

March 25, 2004

Question

What is the place of decontamination with activated charcoal in drug overdose? In several emergency departments where I have previously worked, it was common practice to administer this in most cases of overdose. However, since working at my current location, poison control never recommends this. What is the current evidence-based recommendation?

Harvey Solomon, MD

Response from Desiree Lie, MD, MSEd

Multiple-dose activated charcoal involves the administration of more than 2 doses of oral activated charcoal to enhance elimination of drugs ingested in acute poisoning. The rationale is that charcoal interrupts the enteroenteric, enterogastric, and enterohepatic circulation of absorbed drugs, whereas unabsorbed drugs will be adsorbed to activated charcoal. The charcoal is prepared from vegetable matter such as peat, wood, coal, or coconut shell. It is then activated by high heat in oxidizing gas, such as steam or carbon dioxide, that increases its surface area to at least 900 m2/g to meet industry standards.

The optimal dose of charcoal is unknown. However, the adult dose ranges from 50 to 100 g per dose, administered at a rate no less than 12.5 g/h or its equivalent. Lower doses of 10-25 g are used in children. When drug-induced vomiting is anticipated (for example, with a theophylline overdose), an intravenous antiemetic is recommended.

Although treatment with charcoal is perceived as simple, inexpensive, and safe and avoids the need for invasive procedures, such as hemodialysis and hemoperfusion, the rationale for use is based primarily on animal studies. Most of the clinical data are based on anecdotal case reports, case series, or observational and crossover volunteer human studies, with 6-10 participants per study. Larger, randomized controlled trials are needed, but conducting such studies are challenged by ethical and methodologic limitations and considerations.

Recommendations for activated charcoal in acute ingestions are provided in the position statement of the American Academy of Clinical Toxicology and European Association of Poison Centres and Clinical Toxicologists. A 1997 statement on single-dose activated charcoal[1] was supplemented by the most recent 1999 statement on multidose activated charcoal.[2]

Core recommendations are summarized as follows:

  • Multiple-dose activated charcoal should only be considered if a patient has ingested a life-threatening amount of carbamazepine, dapsone, phenobarbital, quinine, or theophylline.

  • There are insufficient data to support or exclude the use of activated charcoal for the elimination of amitriptyline, dextropropoxyphene, digoxin, digitoxin, disopyramide, nadolol, phenylbutazone, phenytoin, piroxicam, and sotalol.

  • The use of multiple-dose charcoal for salicylate poisoning is controversial. One animal study and 2 of 4 volunteer studies did not demonstrate improved clearance, whereas 2 volunteer studies suggested improvement.[2]

  • On the basis of existing experimental and clinical studies that show no efficacy, multidose activated charcoal is not recommended for the elimination of astemizole, chlorpropamide, doxepin, imipramine, meprobamate, methotrexate, sodium valproate, tobramycin, and vancomycin.

  • The need for concurrent administration of cathartics such as sorbitol remains unproven and is not recommended. In particular, these should not be used in children because of possible fluid and electrolyte disturbances.

Absolute contraindications include unprotected airway, intestinal obstruction, a gastrointestinal tract that is not intact, and decreased peristalsis. Potential complications include transient constipation (especially in nonambulatory patients), bowel obstruction, regurgitation, and aspiration, with consequent pulmonary complications (including death) if the nasogastric tube is incorrectly placed. Emesis is more frequent with sorbitol administration and less frequent with aqueous activated charcoal.

In summary, physicians should base the clinical decision to use activated charcoal for acute ingestions on best judgment according to available evidence the presence of contraindications, and the effectiveness and availability of alternative treatment.

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