Ferrous Salts: Injectable Iron Solutions (50 mg/mL)

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(a) Iron Dextran Injection 50 mg/mL

Description

Iron Dextran Injection 50 mg/mL is a sterile, dark reddish-brown colloidal solution containing a complex of ferric hydroxide and dextran. Each milliliter provides 50 milligrams of elemental iron. It is designed for intravenous (IV) or intramuscular (IM) administration, offering a potent and efficient way to treat severe iron deficiency anemia, especially when oral iron therapy is ineffective or contraindicated.

Advantages

• Effective for Severe Deficiency: Highly effective for rapid and significant repletion of iron stores in severe iron deficiency anemia.
• Alternative to Oral Iron: Provides a crucial option for patients who cannot tolerate oral iron due to severe gastrointestinal side effects, or who have malabsorption conditions (e.g., inflammatory bowel disease, gastric bypass).
• Reduces Transfusion Needs: Can significantly reduce or eliminate the need for red blood cell transfusions, thereby avoiding associated risks.
• Convenient Dosing: Allows for the administration of a large total dose of iron in one or a few sessions, offering more convenience compared to daily oral therapy.
• Suitable for High-Dose Needs: Particularly useful for patients requiring substantial iron repletion in a relatively short period.

Uses

Iron Dextran Injection 50 mg/mL is primarily used for the treatment of:

• Iron Deficiency Anemia: In patients with documented iron deficiency where oral iron therapy is ineffective, not tolerated, or contraindicated. This includes:
  • Patients with chronic blood loss (e.g., hereditary hemorrhagic telangiectasia, severe menorrhagia).
  • Patients with malabsorption syndromes (e.g., Crohn’s disease, celiac disease, gastric bypass patients).
  • Patients on hemodialysis receiving erythropoietin.
  • Post-surgical iron deficiency.
• Iron Replacement: To replenish iron stores rapidly after significant blood loss.

Nature

Iron Dextran is a colloidal complex of ferric oxyhydroxide (Fe$^{3+}$) and dextran, a large polysaccharide chain.

Its mechanism of action involves:

1. Uptake by Reticuloendothelial System (RES): After IV or IM administration, the relatively large iron dextran complex is primarily taken up by cells of the reticuloendothelial system (macrophages) in the liver, spleen, and bone marrow.
2. Gradual Iron Release: Within these RES cells, the dextran component is slowly metabolized, allowing for a gradual and controlled release of elemental iron.
3. Binding to Transferrin: The released elemental iron then binds to transferrin, the body’s primary iron transport protein in the plasma.
4. Delivery for Hemoglobin Synthesis: Transferrin transports the iron to the bone marrow, where it is incorporated into the heme portion of hemoglobin within developing red blood cells (erythroblasts).
5. Storage: Any surplus iron is stored in the body, predominantly in the liver, spleen, and bone marrow, as ferritin and hemosiderin.

The dextran complex ensures a slow release of iron, which minimizes the amount of free, potentially toxic, iron in the circulation. Historically, some high-molecular-weight iron dextran formulations were associated with a higher risk of severe hypersensitivity reactions, although newer, low-molecular-weight formulations generally have an improved safety profile.

Storage

• Room Temperature: Store Iron Dextran Injection 50 mg/mL at controlled room temperature, typically between 20∘C to 25∘C (68∘F to 77∘F).
• Protect from Light: Keep the vials or ampoules in their original carton to protect them from light, which can cause degradation.
• Do Not Freeze: Freezing can compromise the integrity of the colloidal solution and should be strictly avoided.
• Single-Dose Vial: Most presentations are for single-dose use. Any unused portion must be discarded immediately after drawing the dose, as they typically do not contain preservatives.
• Keep Out of Reach of Children: Store securely, completely out of the sight and reach of children and unauthorized individuals.
• Check Expiry Date: Always check the expiry date on the packaging. Do not use the injection beyond this date.

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(b) Iron Sorbitol Citrate Complex Injection 50 mg/mL

Description

Iron Sorbitol Citrate Complex Injection 50 mg/mL is a sterile colloidal solution containing ferric iron complexed with sorbitol and citric acid. Each milliliter provides 50 milligrams of elemental iron. This formulation was historically developed primarily for intramuscular (IM) administration to treat iron deficiency anemia in patients for whom oral iron is not feasible or effective.

Advantages

• Effective Iron Repletion: Provides a direct and effective means to supply elemental iron to correct iron deficiency anemia.
• Alternative to Oral Iron: Offers a viable option for patients who cannot tolerate or adequately absorb oral iron supplements.
• Rapid Correction: Can lead to a quicker increase in hemoglobin levels compared to oral iron, particularly in severe cases.
• Avoids Gastrointestinal Side Effects: Bypasses the digestive system, thereby avoiding common gastrointestinal side effects associated with oral iron.

Uses

Iron Sorbitol Citrate Complex Injection 50 mg/mL is primarily used for the treatment of:

• Iron Deficiency Anemia: In patients where oral iron is unsuitable, ineffective, or when a rapid response is required. This often includes:
  • Patients with chronic kidney disease.
  • Patients with malabsorption syndromes.
  • Patients with chronic blood loss.
  • Pre- and post-operative iron therapy when rapid iron repletion is needed.

Nature

Iron Sorbitol Citrate Complex is a colloidal solution of ferric iron (Fe$^{3+}$) complexed with sorbitol and citric acid. These complexing agents stabilize the iron in solution and facilitate its systemic delivery.

Its mechanism of action involves:

1. Direct Systemic Delivery: When administered (historically IM), the complex delivers elemental iron directly into the systemic circulation, bypassing the gastrointestinal tract.
2. Iron Release and Transport: The iron is gradually released from the sorbitol-citrate complex in the bloodstream. It then binds to transferrin, the body’s iron-transport protein.
3. Hemoglobin Synthesis: Transferrin carries this iron to the bone marrow, where it is efficiently utilized for the synthesis of hemoglobin, leading to increased red blood cell production.
4. Storage: Any excess iron is incorporated into the body’s iron storage proteins, such as ferritin and hemosiderin, replenishing iron reserves.

This complex historically offered a balance between rapid absorption (due to its smaller molecular size compared to some iron dextran formulations) and a controlled release of iron. However, it was notably associated with a higher risk of local staining (brown discoloration) at the intramuscular injection site and potential for transient dark urine. Due to these limitations and the development of newer, safer, and more convenient IV iron preparations, its use has largely declined in many clinical practices in favor of more modern intravenous iron complexes.

Storage

• Cool, Dry Place/Room Temperature: Store Iron Sorbitol Citrate Complex Injection at controlled room temperature, typically between 20∘C to 25∘C (68∘F to 77∘F). It’s generally advised to keep it in a cool and dry place, away from direct sunlight.
• Protect from Light: Keep the ampoules or vials in their original packaging to shield them from light, which can affect the product’s stability.
• Do Not Freeze: Freezing can damage the solution and should be avoided.
• Single-Dose Vial: This product is typically supplied in single-dose containers. Any unused portion must be discarded immediately after drawing the dose, as these formulations usually do not contain preservatives.
• Keep Out of Reach of Children: Store the medication securely, completely out of the sight and reach of children and unauthorized individuals.
• Check Expiry Date: Always check the expiry date on the packaging. Do not use the injection beyond this date.