1. Clinical Overview
Iron Isomaltoside is a next-generation, stable, non-dextran, parenteral iron-carbohydrate complex used for the rapid and efficient correction of iron deficiency and iron deficiency anemia (IDA). It consists of an iron(III)-oxyhydroxide core stabilized by a carbohydrate shell of isomaltoside 1000, allowing for controlled release of bioavailable iron to replenish iron stores and support erythropoiesis. It is characterized by a low immunogenic potential and a favorable safety profile, permitting administration of high single doses (up to 20 mg/kg or 1000 mg) in a single, short (15-30 minute) intravenous infusion.
| Onset | Duration | Bioavailability |
|---|---|---|
| Reticulocyte count begins to increase within 3-7 days. A significant rise in hemoglobin is typically observed within 2-4 weeks. | The replenishment of iron stores is long-lasting, often sufficient to correct anemia and maintain iron levels for several months, depending on the underlying cause and ongoing iron losses. | 100% via intravenous administration. Oral bioavailability is 0% as it is not administered via the oral route. |
2. Mechanism of Action
Iron Isomaltoside is a colloidal solution where an iron(III)-oxyhydroxide core is surrounded by a matrix of isomaltoside 1000, a carbohydrate polymer derived from sucrose. Following intravenous administration, the complex is recognized and phagocytosed as a whole by macrophages of the reticuloendothelial system (RES), primarily in the liver and spleen. Within the macrophage lysosomes, the isomaltoside shell is enzymatically cleaved, releasing ionic iron (Fe3+) into the intracellular labile iron pool. This iron is then reduced to Fe2+, transported out of the macrophage via ferroportin, oxidized back to Fe3+, and bound to plasma transferrin. Transferrin-bound iron is delivered to erythroid precursor cells in the bone marrow for incorporation into hemoglobin, or to storage sites as ferritin and hemosiderin.
3. Indications & Uses
- Iron Deficiency Anemia (IDA) in adults when oral iron preparations are ineffective or cannot be used
- Iron Deficiency Anemia in adult patients with Chronic Kidney Disease (CKD)
4. Dosage & Administration
Adult Dosage: Dose is individualized based on body weight and total iron deficit calculated using the Ganzoni formula: Total iron deficit (mg) = Body weight (kg) x (Target Hb - Actual Hb in g/dL) x 2.4 + Iron stores (500 mg). Alternatively, a simplified weight-based dosing: 20 mg/kg up to a maximum single dose of 1000 mg. Can be administered as a single total dose infusion or in divided doses.
Administration: For IV infusion: Dilute required dose in maximum 250 mL of 0.9% Sodium Chloride injection. Infuse over at least 15-30 minutes. For slow IV injection (undiluted): Administer at a rate of 1 mL (100 mg) per minute, not exceeding 2.5 mL (250 mg) per injection site. A test dose is not mandatory but recommended for patients with history of drug allergies. Monitor patient during and for at least 30 minutes after administration for hypersensitivity reactions.
5. Side Effects
Common side effects may include:
- Transient taste disturbance (metallic taste)
- Headache
- Nausea
- Injection site reactions (pain, swelling, discoloration)
- Flushing
- Dizziness
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Oral Iron Supplements | Concurrent use is generally not required and may increase risk of gastrointestinal side effects without added benefit during IV therapy. | Moderate |
| Angiotensin-Converting Enzyme (ACE) Inhibitors | May potentially increase risk of hypersensitivity-like reactions. Monitor closely. | Moderate |
| Dimercaprol | Chelating agent; may form a toxic complex with iron. Contraindicated in iron overload from IV iron. | Major |
7. Patient Counselling
- Do inform your doctor about any allergies, especially to other IV iron or drugs.
- Do report any history of asthma, eczema, or multiple drug allergies.
- Do not take oral iron supplements concurrently unless specifically advised by your doctor.
- Do plan to rest for 30-60 minutes after the infusion if you feel dizzy.
- Do keep the injection site clean and dry.
8. Toxicology & Storage
Overdose: Symptoms of acute iron overload: Nausea, vomiting, abdominal pain, diarrhea, hypotension, tachycardia, lethargy, pallor, cyanosis, metabolic acidosis, and potentially shock and multi-organ failure. Chronic overload leads to hemosiderosis affecting liver, heart, and endocrine glands.
Storage: Store in original carton to protect from light. Do not freeze. Store at a temperature not exceeding 25°C. Keep out of reach and sight of children. Once the vial is opened, use immediately. Discard any unused portion. Do not use if the solution is discolored or contains visible particles.