What is the recommended dose of ferroxycarboxy maltose (intravenous iron replacement therapy) injection?

Ferric Carboxymaltose Dosing

Ferric carboxymaltose should be dosed at up to 1000 mg of iron per week (750 mg per dose in the US), administered either as an undiluted slow IV bolus over 15 minutes or as an infusion diluted in 100-250 mL normal saline over 15-30 minutes, with the total initial iron need calculated based on body weight and hemoglobin levels rather than ferritin or transferrin saturation. 1, 2

Dosing Calculation and Administration

Initial Dose Determination

• Calculate the total iron need based on body weight and hemoglobin levels, not ferritin or TSAT levels 1
• The maximum recommended cumulative dose is 1000 mg iron (20 mL) per week in Europe and Asia 1, 3
• In the United States, FCM is distributed as 750 mg vials with labeling recommending two doses 1 week apart 2

Administration Methods

Option 1: Undiluted Bolus Injection (Preferred for Convenience)

• Administer as an undiluted slow bolus injection at 100 mg/min 1
• For a 1000 mg dose, this takes 15 minutes 1, 2, 3
• This method has been proven safe in clinical trials with no serious adverse events 4

Option 2: Diluted Infusion

• For 500 mg dose: dilute 10 mL FCM in maximum 100 mL sterile 0.9% sodium chloride, infuse over minimum 6 minutes 1
• For 1000 mg dose: dilute 20 mL FCM in maximum 250 mL sterile 0.9% sodium chloride, infuse over minimum 15 minutes 1
• Do not over-dilute as this affects drug stability 1
• The American Journal of Hematology recommends dilution in 100 mL normal saline and infusion over 20-30 minutes 2

Monitoring Requirements

Immediate Post-Administration

• Observe patients for at least 30 minutes following each IV injection for adverse effects 1, 2
• Ensure proper IV line placement to avoid extravasation and skin staining 1

Follow-Up Monitoring

• Re-evaluate iron status at 3 months after initial correction dose 1, 5
• Avoid early re-evaluation within 4 weeks of IV iron administration, as ferritin levels increase markedly and cannot be used as an accurate indicator of iron status during this time 1, 2, 6, 5
• Laboratory evaluation should include CBC and iron parameters (ferritin, percent transferrin saturation) at 4-8 weeks after the last infusion 2, 6
• Hemoglobin concentrations should increase within 1-2 weeks of treatment and should increase by 1-2 g/dL within 4-8 weeks 2, 6
• Consider routine iron status evaluation 1-2 times per year in patients with chronic heart failure 1, 5

Contraindications and Cautions

Absolute Contraindications

• Hypersensitivity to FCM or any of its excipients 1, 5
• Known serious hypersensitivity to other parenteral iron products 1, 5
• Anemia not attributed to iron deficiency (e.g., other microcytic anemias) 1, 5
• Evidence of iron overload or disturbances in iron utilization 1, 5
• Do not administer if hemoglobin >15 g/dL 2, 6

Use With Caution

• Acute or chronic infection: stop treatment in patients with ongoing bacteremia 1, 5
• Known drug allergies, especially history of severe asthma, eczema, or other atopic allergies (increased risk of hypersensitivity reactions) 1, 5
• Immune or inflammatory conditions (e.g., systemic lupus erythematosus, rheumatoid arthritis) have increased risk of hypersensitivity reactions 1, 5
• Repeat infusions: FCM has been associated with treatment-emergent hypophosphatemia (58% incidence) and should be avoided in patients requiring frequent repeat infusions 2

Important Clinical Considerations

Advantages Over Other Formulations

• FCM allows for high-dose administration (up to 1000 mg) in a short time frame (15 minutes), compared to iron sucrose's maximum of 200 mg per dose requiring 4-7 clinic visits 2, 3, 7
• Lower risk of anaphylaxis compared to iron dextran, with no reported cases of anaphylaxis to date 2
• More convenient than low molecular weight iron-dextran, which requires 4-6 hours for total dose infusion 2

Common Pitfalls to Avoid

• Do not evaluate iron parameters too early: circulating iron interferes with assays leading to inaccurate results if checked within 4 weeks 1, 2, 6
• Monitor for hypophosphatemia: most cases are biochemically moderate (serum phosphate 0.32-0.64 mmol/L) and asymptomatic, resolving without intervention, but this occurs in 58% of patients 2
• Stop immediately if extravasation occurs to prevent skin staining 1
• Flushing during injection is common and transient headache may occur in subsequent weeks 4

Setting and Personnel Requirements

• FCM can be administered in hospital or community settings where staff are trained and equipped to monitor for and manage hypersensitivity reactions 1
• The risk of hypersensitivity reactions is low (≥0.1% to <1.0% frequency) 1