Iron Toxicity

Iron Formulations and Elemental Iron Composition:
  Iron Formulation Elemental Iron Composition
Ionic Ferrous fumarate (PO) 33%
Ferrous chloride (PO) 28%
Ferrous sulfate (PO) 20%
Ferrous lactate (PO) 19%
Ferrous gluconate (PO) 12%
Ferrous gluconate (IV) 1.25%
Nonionic Carbonyl iron (PO) 98%
Iron polysaccharide (PO) 46%
Ferric hydroxide dextran (IV) 10% or 20%
Iron sucrose (IV) 2%
Chelated Ferrous bisglycinate (PO) 20%
Iron glycinate (PO) 27%
Example: A 325-milligram ferrous sulfate tablet is 20% elemental iron and thus only 65 milligrams of elemental iron per tablet. Iron sucrose is a 2% elemental iron solution and contains 20 milligrams of elemental iron per 1 mL.


Patients without onset of vomiting 6 hours after iron exposure will not have significant systemic toxicity


Predicted Toxicity of Iron Ingestion:
Predicted Clinical Effects Elemental Iron Dose* Serum Iron Concentration
(within 4–6 h of ingestion)
Nontoxic or mild GI symptoms <20 mg/kg <300 mcg/dL
Expected significant GI symptoms and potential for systemic toxicity 20-60 mg/kg 300-500 mcg/dL
Moderate to severe systemic toxicity >60 mg/kg >500 mcg/dL
Severe systemic toxicity and increased morbidity -- >1000 mcg/dL
*Elemental iron dose by history.
Serum iron concentration obtained within 4–6 h of ingestion.


Classically described as five phases of toxicity (see Table 6.24), as follows:



A 17-month-old boy came to the hospital with lethargy and hematemesis following a large ingestion of iron supplement pills. Despite orogastric lavage and whole-bowel irrigation, iron pills and fragments can be visualized in the stomach 4 hours after ingestion