Activated charcoal reduces the gastric absorption of iron compounds
Date First Published:
March 1, 2000
Last Updated:
January 10, 2002
Report by:
Steve Jones, Clinical Research Fellow (MRI)
Search checked by:
Baha Ali, MRI
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.
Search Details:
[(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.
Outcome:
17 papers found of which only 1 paper addressed the question.
Relevant Paper(s):
| Study Title | Patient Group | Study type (level of evidence) | Outcomes | Key results | Study Weaknesses |
|---|---|---|---|---|---|
| Prevention of gastriointestinal iron absorption by chelation from an orally administered premixed deferoxamine/charcoal slurry. Gomez HF, McClafferty HH, Flory D, et al. 1997, USA | 11 healthy adult volunteers | Controlled, prospective cross-over study | Maximum serum iron concentration:<br><br>- iron only<br><br>-iron plus activated charcoal (AC)<br><br>-iron plus AC plus desferrioxamine | <br><br><br>150mcg/dL +/-36<br><br>94mcg/dL +/-23<br><br><br>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:<br><br>-iron only<br><br>-iron plus AC<br><br>-iron plus AC plus desferrioxamine | <br><br><br>3.5hr +/-0.3<br><br>3.6hr +/-0.5<br><br>3.0hr +/-1.0 |
Author Commentary:
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.
Bottom Line:
Giving oral activated charcoal may well reduce gastric absorption after iron overdose.
References:
- Gomez HF, McClafferty HH, Flory D, et al.. Prevention of gastriointestinal iron absorption by chelation from an orally administered premixed deferoxamine/charcoal slurry.