Ingesting above 120 mg/kg may be fatal. The therapeutic dose for iron deficiency anemia is 3–6 mg/kg/day. Individuals who have ingested less than 20 mg/kg of elemental iron typically do not exhibit symptoms. It is unlikely to get iron poisoning from diet alone with iron supplements being the cause of overdose. The amount of elemental iron in an iron supplement can be calculate based on the percentage it constitutes for per tablet. For example, a 300 mg tablet of ferrous fumarate will contain 100 mg of elemental iron or 33%. Ferrous sulfate contains 20% elemental iron per mg of mineral salt
Ferrous gluconate contains 12% elemental iron per mg of mineral salt
Ferrous fumarate contains 33% elemental iron per mg of mineral salt

Diagnosis
Iron toxicity is primarily a clinical diagnosis that involves getting a detailed patient history and physical examination of the individuals signs and symptoms. Information such as how much iron was ingested and the timing should be gathered to assess the level of toxicity. Signs for severe iron poisoning should be evaluated such as any confusion or extreme lethargy, increased heart rates, low blood pressure for adults. In children, signs of shock can be noted with behavioral changes such as decreased responsiveness, crying, and inability to focus. Persistent vomiting is often associated with iron poisoning and also used to determine severity of iron poisoning. Laboratory tests such as measuring the peak serum iron level after 4 to 6 hours of ingestion can be useful in determining the severity of iron toxicity.
It is a chelating agent and binds to free iron in the body in order to be eliminated by the kidneys into urine. Dosing of deferoxamine should be determined through consultation with a toxicologist but is typically continuously infused at 15 mg/kg to 35 mg/kg per hour and not exceeding the maximum daily dose of 6 grams for adults. In pediatric patients, doses should not exceed 15 mg/kg per hour. recommended duration of treatment is until symptoms have resolved which is usually 24 hours. In non-fatal cases of iron poisoning where there is liver failure, liver transplantation may be necessary.Treatment of iron poisoning should be based on clinical presentation, peak serum iron levels and other laboratory results. As a general guideline, patients who have ingested lower doses of elemental iron, have a peak serum iron level less than 500mcg/dL and are asymptomatic or only exhibit mild gastrointestinal symptoms typically do not require treatment and should be monitored for 6 hours after ingestion. In cases where high doses of elemental iron have been ingested and the patient is exhibiting signs and symptoms of severe systemic iron poisoning, supportive care measures like volume resuscitation and deferoxamine should be initiated immediately. A quick response to iron poisoning can significantly improve clinical outcomes. See also
Overnutrition
Iron overload

References
External links
Iron poisoning in General Practice Notebook
Iron Poisoning at WebMD
Iron Poisoning Merck Manual