Elemental Iron

Usage

Elemental iron is primarily used to treat and prevent iron deficiency and iron deficiency anemia. Its pharmacological classification is as a mineral supplement and hematinic. It works by providing the necessary iron for hemoglobin synthesis, myoglobin production, and various enzymatic processes.

Alternate Names

While “elemental iron” itself doesn’t have alternate names, different iron salts used to supplement it have varying names (e.g., ferrous sulfate, ferrous gluconate, ferrous fumarate, ferric derisomaltose, iron sucrose, iron polymaltose). Brand names for iron supplements are numerous and vary regionally.

How It Works

Pharmacodynamics: Iron is crucial for oxygen transport and storage within the body. It is incorporated into hemoglobin in red blood cells, which carry oxygen throughout the body. Iron is also a component of myoglobin, which stores oxygen in muscle tissue. Furthermore, it plays a role in various enzyme systems.

Pharmacokinetics:

• Absorption: Iron is primarily absorbed in the duodenum and upper jejunum. Absorption is enhanced in an acidic environment and by the presence of vitamin C. Factors such as antacids, tea, coffee, and certain foods can inhibit iron absorption.
• Distribution: Following absorption, iron binds to transferrin in the blood and is transported to various tissues for utilization or storage, mainly in the bone marrow, liver, and spleen.
• Metabolism: Iron is stored as ferritin or hemosiderin within cells.
• Elimination: Iron excretion is limited. Small amounts are lost through shedding of mucosal and skin cells, as well as in bile, sweat, and urine.

Mode of Action: Iron exerts its therapeutic effect by being incorporated into heme, the iron-containing component of hemoglobin. This process takes place in developing red blood cells within the bone marrow. Increased hemoglobin levels enhance the oxygen-carrying capacity of the blood, thereby correcting anemia and improving tissue oxygenation.

Dosage

Standard Dosage

Adults:

Oral iron is generally the first line of treatment for iron deficiency. Dosages typically range from 100-200 mg of elemental iron per day, divided into two or three doses. Lower doses (e.g., 40-80 mg elemental iron on alternate days) may be as effective with fewer gastrointestinal side effects.

Children:

Pediatric dosing is weight-based, typically 3-6 mg/kg/day of elemental iron, divided into doses. For infants with low birth weight (<2500g) or premature birth (<37 weeks), a specialist consultation is recommended regarding iron supplementation.

Special Cases:

• Elderly Patients: Lower doses (15-50 mg/day elemental iron) may suffice due to potential for reduced tolerance.
• Patients with Renal Impairment: In non-dialysis-dependent CKD, oral iron is usually given initially. Intravenous iron is usually considered if oral iron is ineffective or not tolerated, or in hemodialysis patients.
• Patients with Hepatic Dysfunction: Caution should be exercised in severe liver disease due to potential for impaired absorption and exacerbation of hepatic encephalopathy due to constipation.
• Patients with Comorbid Conditions: Conditions like inflammatory bowel disease, gastric bypass surgery, or chronic heart failure may necessitate intravenous iron administration.

Clinical Use Cases

Dosages are typically guided by specific clinical protocols and should be determined in consultation with specialists. Iron supplementation may be administered pre-operatively in surgical patients with low iron stores (ferritin <100 mcg/L) anticipated to have substantial blood loss.

Dosage Adjustments

Dosage adjustments are based on patient factors such as hemoglobin levels, ferritin levels, and tolerance to therapy. Lower doses or alternate-day dosing may be employed to minimize side effects.

Side Effects

Common Side Effects:

Constipation, nausea, vomiting, abdominal pain, dark stools, and metallic taste are common gastrointestinal side effects. Liquid iron preparations can stain teeth.

Rare but Serious Side Effects:

Allergic reactions (including anaphylaxis) can occur with intravenous iron preparations.

Long-Term Effects:

Iron overload (hemochromatosis or hemosiderosis) can develop with excessive long-term use, especially with parenteral iron.

Adverse Drug Reactions (ADR):

Severe hypersensitivity reactions with intravenous iron require immediate medical intervention.

Contraindications

• Iron overload (hemochromatosis, hemosiderosis)
• Anemia not caused by iron deficiency (e.g., hemolytic anemia, megaloblastic anemia, thalassemia)
• Known hypersensitivity to specific iron preparations

Drug Interactions

Iron can interact with several medications, including:

• Antacids, H2 blockers, and proton pump inhibitors: Reduced iron absorption.
• Tetracyclines, quinolones, levodopa: Reduced absorption of both drugs.
• Levothyroxine: Reduced levothyroxine absorption.

Pregnancy and Breastfeeding

Iron supplementation is often recommended during pregnancy and breastfeeding to address increased iron demands. Oral iron is generally considered safe; however, some gastrointestinal side effects may occur. Dosage requirements are higher during pregnancy (typically 30 mg elemental iron/day).

Drug Profile Summary

• Mechanism of Action: Replenishes iron stores for hemoglobin synthesis and other essential functions.
• Side Effects: GI disturbances (constipation, nausea, etc.), tooth staining (liquid formulations).
• Contraindications: Iron overload, non-iron deficiency anemia, hypersensitivity.
• Drug Interactions: Antacids, tetracyclines, quinolones, levodopa, levothyroxine.
• Pregnancy & Breastfeeding: Generally safe; increased dosage requirements in pregnancy.
• Dosage: Adults: 100-200 mg elemental iron/day; Children: 3-6 mg/kg/day.
• Monitoring Parameters: Hemoglobin, ferritin, transferrin saturation.

Popular Combinations

Iron is often combined with vitamin C to enhance absorption. In some cases, it may be combined with other hematinics like folic acid or vitamin B12, particularly in pregnancy or specific types of anemia.

Precautions

• Assess iron status before initiating therapy (hemoglobin, ferritin, transferrin saturation).
• Screen for allergies to iron preparations.
• Monitor for gastrointestinal side effects.
• Advise patients about potential tooth staining with liquid formulations.

FAQs (Frequently Asked Questions)

Q1: What is the recommended dosage for Elemental Iron?

A: Adults: 100-200 mg elemental iron/day, divided into 2-3 doses; Children: 3-6 mg/kg/day, divided into doses. Lower doses or alternate-day dosing may be considered to improve tolerance.

Q2: What are the common side effects of iron supplementation?

A: Common side effects include constipation, nausea, vomiting, abdominal discomfort, dark stools, and a metallic taste.

Q3: How can iron absorption be maximized?

A: Iron absorption is enhanced by taking it on an empty stomach with vitamin C. Avoid co-administration with antacids, tea, coffee, and dairy products.

Q4: What are the contraindications to oral iron therapy?

A: Contraindications include iron overload syndromes, anemias not caused by iron deficiency (e.g., hemolytic anemia, thalassemia), and hypersensitivity to specific iron preparations.

Q5: When is intravenous iron therapy indicated?

A: Intravenous iron is typically reserved for patients who cannot tolerate or absorb oral iron, those with severe iron deficiency anemia, or individuals with certain comorbid conditions (e.g., inflammatory bowel disease, chronic kidney disease).

Q6: How should iron be dosed in pregnancy?

A: Iron requirements increase during pregnancy. Supplementation of 30 mg elemental iron per day is generally recommended.

Q7: What are the risks of long-term iron supplementation?

A: Excessive long-term use can lead to iron overload (hemochromatosis or hemosiderosis), which can damage organs like the liver, heart, and pancreas.

Q8: How should iron be dosed in patients with renal impairment?

A: Oral iron may be used in non-dialysis-dependent chronic kidney disease. Intravenous iron is typically preferred for patients on hemodialysis or those with inadequate response to oral iron.

Q9: What are the signs and symptoms of iron toxicity?

A: Early symptoms include nausea, vomiting, abdominal pain, and diarrhea. Severe toxicity can lead to organ damage, shock, and even death.

Q10: What is the role of monitoring during iron therapy?

A: Monitoring hemoglobin, ferritin, and transferrin saturation levels are essential to assess response to therapy and to prevent iron overload. The frequency of monitoring should be determined based on the individual patient’s condition and the route of iron administration (oral vs. intravenous).