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Three Part Question

In [a patient with an iron overdose] is [activated charcoal better than nothing] at [reducing gastric absorption, mortality or morbidity]?

Clinical Scenario

A young woman presents to the emergency department having taken an overdose of her iron tablets. She is in an emotionally distressed state but is cardiovascularly stable and requests treatment. It has been less than 2 hours since she took the tablets and you prescribe activated charcoal. You wonder whether this will actually do her any good.

Search Strategy

Medline 1966-11/01 using the OVID interface.
[(exp poisoning OR poisoning.mp OR exp overdose OR overdose.mp) AND (exp iron OR exp iron compounds OR iron.mp) AND (exp charcoal OR charcoal.mp OR activated charcoal.mp) LIMIT to human AND English.

Search Outcome

17 papers found of which only 1 paper addressed the question.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Gomez HF et al, 1997, USA	11 healthy adult volunteers	Controlled, prospective cross-over study	Maximum serum iron concentration: - iron only -iron plus activated charcoal (AC) -iron plus AC plus desferrioxamine	150mcg/dL +/-36 94mcg/dL +/-23 37mcg/dL +/-13 (p 0.0017)	Healthy volunteers Strict exclusion criteria Physiological doses of iron rather than toxic doses
			Time to maximum serum iron concentration: -iron only -iron plus AC -iron plus AC plus desferrioxamine	3.5hr +/-0.3 3.6hr +/-0.5 3.0hr +/-1.0

Comment(s)

This study partially addresses the question and concludes that more work needs to be done. In the doses given to these healthy patients, activated charcoal reduced absorption; this was reduced further by adding desferrioaxamine to the oral solution. Toxic doses are considered to be 4 fold higher than the doses used in the study and treatment in this group of patients depends on clinical features.

Clinical Bottom Line

Giving oral activated charcoal may well reduce gastric absorption after iron overdose.

References

1. Gomez HF, McClafferty HH, Flory D, et al. Prevention of gastriointestinal iron absorption by chelation from an orally administered premixed deferoxamine/charcoal slurry. Ann Emerg Med 1997;30(5):587-92.