Iron is a common ingredient in many multivitamin preparations and is widely available in multiple forms including liquid, tablets or capsules, and chewables - for both adults and children.
Iron toxicity is determined by the amount of elemental iron ingested per kilogram of body weight. The Tennessee Poison Center refers patients to health care facilities when the ingested dose is 40mg/kg of elemental iron. The amount of elemental iron must be calculated as formulations vary.
Iron poisoning causes significant irritation to the gastrointestinal tract and initial clinical symptoms include nausea, vomiting, diarrhea, and abdominal pain which can all lead to excessive fluid loss. Iron is corrosive to the GI mucosa and gastrointestinal bleeding can be life-threatening. Toxic amounts of iron also cause cellular toxicity through inhibition of oxidative phosphorylation, a breakdown of the electron transport chain in the mitochondria. Without treatment, seizures, shock, coma, multi-organ failure, and death can occur.
Electrolytes, BUN, SCr, LFTs, CBC and serum iron concentrations should be obtained. KUB should be performed to visualize iron tablets – if present, whole bowel irrigation may be indicated. The antidote is deferoxamine which chelates iron. When iron concentrations reach 350mcg/dL, and patients are symptomatic, deferoxamine administration may be considered. When iron levels reach 500mcg/dL, with or without symptoms deferoxamine is usually indicated
As always, call the Poison Center (at 1-800-222-1222) to discuss the specific therapy required for your patient with iron ingestion.
This question was prepared by: Donna Taylor, RN CSPI
There are challenges with treatment of iron overdose. Deferoxamine can cause hypotension, which is the last thing you need if your patient is already hypotensive (free iron is a potent vasodilator, GI bleeding/fluid losses). Yet deferoxamine is the only agent that will chelate iron. Also, the corrosive nature of iron in the GI tract can cause GI bleeding so patients may need transfusion. There is certainly a clinical component to the diagnosis of iron toxicity. If the patient is severely symptomatic on presentation, get the deferoxamine ready and call the Poison Center.
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Donna Seger, MD
Tennessee Poison Center
Poison Help Hotline: 1-800-222-1222