Ferrous iron poisoning caused

High doses of iron salts by mouth can cause severe gastrointestinal irritation and even necrosis of the mucous membrane. Autopsy shows severe damage to brain and liver. Iron poisoning is particularly dangerous in children. Sustained-release forms are safer in homes where heedless parents live with small children. Ferrous sulphate is the most toxic. 

Pregnant women require an increased an amount of iron, but they need to avoid a megadose in the first trimester because it might cause birth defects. Larger doses of iron are necessary in the second and third trimester. Iron is absorbed in the intestine where it enters plasma as heme or is stored as ferritin in the liver, spleen, and bone marrow. Food, the antibiotic tetracychne, and antacids decrease absorption up to 50% of iron. However, the patient should take iron with food to avoid GI discomfort. Vitamin C may slightly increase iron absorption. Iron toxicity is a serious cause of poisoning in children. Toxicity can develop with as few as 10 tablets of ferrous sulfate (3g) taken at one time—and can be fatal within 12 to 48 hours. 

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