1. Clinical Overview
Ferric Carboxymaltose (FCM) is a next-generation, stable, non-dextran, parenteral iron complex used for the rapid correction of iron deficiency anemia (IDA). It consists of a polynuclear iron(III)-hydroxide core stabilized by a carbohydrate shell, allowing for controlled delivery of iron to target tissues. It is a preferred choice in the Indian setting due to its ability to administer large doses (up to 1000 mg) in a single, short (15-minute) IV infusion, leading to rapid hemoglobin repletion and iron store replenishment with a favorable safety profile.
| Onset | Duration | Bioavailability |
|---|---|---|
| Reticulocyte response begins within 3-7 days. | Hemoglobin levels typically normalize within 2-4 weeks. Iron stores are replenished for up to 3-4 months post-infusion. | 100% via intravenous route. |
2. Mechanism of Action
Ferric carboxymaltose is a macromolecular complex where iron is tightly bound in a polynuclear ferric oxyhydroxide core, surrounded by a carbohydrate shell of carboxymaltose. Following intravenous administration, it is taken up by the reticuloendothelial system (RES), primarily in the liver and spleen. Within the RES, iron is released from the complex in a controlled manner, binds to endogenous transferrin, and is transported to the bone marrow for incorporation into hemoglobin in developing red blood cells. The remaining iron is stored as ferritin or hemosiderin.
3. Indications & Uses
- Iron Deficiency Anemia (IDA) in adults where oral iron is ineffective or cannot be used.
- Iron Deficiency Anemia in adults with chronic kidney disease (CKD) not on dialysis.
4. Dosage & Administration
Adult Dosage: Dose is calculated based on body weight and hemoglobin (Hb) level using the Ganzoni formula: Total iron deficit (mg) = Body weight (kg) x (Target Hb - Actual Hb) (g/dL) x 2.4 + Iron stores (500 mg). A simplified dosing is often used: For patients ≥50 kg: 1000 mg as a single dose or 20 mg/kg, up to a maximum single dose of 1000 mg. For patients <50 kg: 15 mg/kg. May be repeated if needed after clinical and laboratory reassessment.
Administration: For IV use only. Must be diluted in 100-250 mL of 0.9% Sodium Chloride Injection. Administer as a slow IV infusion over at least 15 minutes. Can also be given as a slow IV injection (undiluted) at a rate of 1 mL (50 mg) per minute, not exceeding total dose of 200 mg per injection site. Test dose is not required but patient should be observed for at least 30 minutes post-infusion for hypersensitivity reactions.
5. Side Effects
Common side effects may include:
- Nausea
- Headache
- Dizziness
- Injection site reactions (pain, swelling, phlebitis)
- Flushing
- Hypertension or hypotension transiently
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Oral Iron Supplements | Concurrent use is not recommended as it may increase risk of gastrointestinal side effects and does not provide additive benefit during IV therapy. | Moderate |
| Dimercaprol | Chelating agent; may form a toxic complex with iron. Contraindicated in iron overload from FCM. | Major |
| ACE Inhibitors (e.g., Enalapril) | May potentiate hypotensive effects during infusion. Monitor blood pressure. | Moderate |
| Phosphate Binders (e.g., Sevelamer) | May be required to manage FCM-induced hypophosphatemia in CKD patients. | Moderate (Therapeutic) |
7. Patient Counselling
- Do inform your doctor about all allergies, especially to other IV iron or injectable drugs.
- Do report any dizziness, breathing difficulty, rash, or chest pain during or after the infusion.
- Do attend follow-up appointments for blood tests to check hemoglobin and iron levels.
- Don't take oral iron supplements while on this therapy unless specifically advised by your doctor.
- Don't miss informing your doctor if you are pregnant, planning pregnancy, or breastfeeding.
8. Toxicology & Storage
Overdose: Symptoms of acute iron overload: Nausea, vomiting, abdominal pain, diarrhea, hypotension, tachycardia, lethargy, pallor, cyanosis, and potentially metabolic acidosis, coagulopathy, hepatic necrosis, and cardiovascular collapse.
Storage: Store below 25°C. Do not freeze. Keep in the original carton to protect from light. The solution should be visually inspected for particulate matter and discoloration before use. Use immediately after dilution. Discard any unused portion. Keep out of reach of children.