Iron Dextran Injection: Effective Iron Replacement Therapy

Mechanism of Action

Iron dextran is a complex of ferric hydroxide and low molecular weight dextran, used primarily to treat iron deficiency anemia. When administered, iron dextran is taken up by macrophages and delivered to the reticuloendothelial system (RES) via endocytosis. The RES separates the components, allowing iron to bind to transferrin, an iron-binding protein that transports iron to the bone marrow. The iron-transferrin complex binds to transferrin receptor 1 (TFR1) on erythroid progenitor cells, where iron is used to synthesize heme, a component of hemoglobin. This process increases red blood cell production and hemoglobin levels, typically observed about 7 days after infusion.

Uses

Iron dextran injection is indicated for:

• Treatment of iron deficiency anemia in patients who cannot tolerate or do not respond to oral iron supplements.
• Patients with chronic kidney disease or malabsorption issues where oral iron is ineffective.

Dosage and Administration

Adults:

• Iron-deficiency anemia: 25-100 mg IV or deep IM qDay PRN. Do not exceed 100 mg (2 mL)/day.
• The total iron dose can be calculated using the formula: Dose = 0.0442(Desired Hgb - Observed Hgb) x Lean BW(kg) + (0.26 × Lean BW).
• Pediatrics:
• 15 kg: Similar to adult dosing, adjusted for lean body weight.
• 5-15 kg: Not to be given in the first 4 months of life. Dose = 0.0442(Desired Hgb - Observed Hgb) x BW(kg) + (0.26 × BW).
• Administration:
• IV: May be administered as a bolus at <50 mg/min or diluted in 250-1000 mL of 0.9% NaCl and infused over 1-6 hours. Observe for allergic reactions and have epinephrine nearby.
• IM: Use the z-track technique for deep IM administration. Observe for allergic reactions.

Storage

Iron dextran injection should be stored at room temperature. Avoid freezing and protect from light.