Must-read: review of single-dose activated charcoal
November 17, 2015, 12:25 am
Activated charcoal for acute overdose: a reappraisal. Juurlink D. Br J Clin Pharmacol 2015 Sep 26 [Epub ahead of print]
The British Journal of Clinical Pharmacology seems to be publishing a series of articles on basic management of the poisoned patient. Several weeks ago we reviewed (and highly recommended) Marco Sivilotti’s excellent discussion of flumazenil, naloxone and the coma cocktail. This current article looking at single-dose activated charcoal (SDAC) is similarly well done, and essential reading.
The author points out that although most poisons bind to activated charcoal some — most notably hydrocarbons, caustics, and the metals lithium and iron — do not. Other factors that might increase the potential benefit of administering SDAC include:
- anticipation of severe toxicity
- absence of contraindications (such as decreased mental status, unprotected airway, uncooperative patient, ileum, or intestinal obstruction)
- lack of effective antidote
- ingestion of modified-release formulation
- ability to administer a reasonable dose of charcoal (50-100 grams) that will be at least 10-40 times the dose of poison
Although in the absence of contraindications charcoal is relatively safe, there are definite risks, including pulmonary aspiration and intestinal obstruction or perforation. The decision whether or not to treat a poisoned patient with SDAC is a clinical one. An important concept hinted at in the paper is that giving SDAC is never mandatory. That decision should be made at the bedside after carefully weighing the possible risks and benefits. I have reviewed a number of cases where the treating clinician was exposed to medical-legal vulnerability because he or she administered SDAC thinking that not doing so would be negligence or a violation of “standard of care.” In many of these cases, SDAC was given through a nasogastric tube to an uncooperative or lethargic patient.
There are several things I especially liked about this paper. The author critically evaluates much of the literature he cites, and refrains from merely relying on the abstract or conclusions. In addition, although many commentators claim — nonsensically, in my view — that SDAC is ineffective if given more than 1 hour after ingestion, this paper argues sensibly that in large potentially severe overdoses or those involving drugs that slow gastric emptying, SDAC may be a reasonable option even hours later if the clinician suspects significant amounts of drug may remain in the gastrointestinal tract.