Oral Administration of Iron Supplements

Dietary Supplements of Iron
Numerous dietary supplements contain iron. Generally, the multimineral/multivitamin supplements containing iron, especially recommended to women, provide about 18 mg iron, which is 100 percent of the daily value (DV) required by a person. Similar supplements for males usually consist of less or no iron. Usually, iron-only supplements provide more than the DV of iron, with many delivering 65 mg of iron (360 percent of the DV). Forms of iron supplements used frequently include ferric and ferrous iron salts, such as ferric citrate, ferrous gluconate, ferric sulfate, and ferrous sulfate. Ferrous iron is more bioavailable than ferric iron due to its higher solubility. When consumed in higher doses (45 mg/day or more), iron supplements can result in gastrointestinal side effects such as constipation and nausea. Other forms of supplemental iron such as carbonyl iron, polysaccharide-iron complexes, heme iron polypeptides, and iron amino-acid chelates, may have lesser gastrointestinal side effects than ferric or ferrous salts. It is recommended that people take iron and calcium supplements at different times during the day as calcium is believed to interfere with iron absorption.

Oral Administration of Iron Supplements

Iron can be supplemented orally in various forms such as ferrous sulfate, the most widely used and well-studied iron salt that is soluble. It can be procured under brand names such as Slow-FE, Fer-Iron, and Feratab. It is available in complex with carbonyl iron, dextran, gluconate, and other salts. The absorption of non-heme iron sources increases due to ascorbic acid and vitamin C. Heme iron polypeptide (HIP), such as proferrin forte and proferrin ES) is used in cases where the usual iron supplements such as ferrous fumarate and ferrous sulfate are not absorbed or tolerated. Another alternative is ferroglycine sulfate or glycine sulfate, which has lesser associated gastrointestinal side-effects than standard salts such as iron fumarate. Since the body’s iron stores are usually depleted, and the body can process only a limited amount of iron (approximately 2 to 6 mg/kg of body mass) without iron poisoning. Thus in many indications, parenteral iron is recommended instead of oral iron, as it has certain disadvantages such as intolerance of oral iron and slow improvement.

Intravenous Administration of Iron Supplements
When oral therapy fails (or is not tolerated) or oral absorption is highly compromised (due to illness or some other conditions), iron therapy (intramuscular or intravenously) is used. Parenteral therapy costs more than iron preparations. It is not suggested at the time of the first trimester of pregnancy. In most cases, the risk of adverse events is lower than blood transfusion upon the usage of intravenous iron such as ferric carboxy maltose. Certain risks attributing to the adverse events associated with soluble iron salts, resulting in toxicity due to damage to cellular macromolecules. Several different molecules, such as sucrose, dextrans, and carboxy maltose are used when the iron is delivered parenterally to limit the damage.