What is the recommended dose of Ferric carboxymaltose (intravenous iron replacement therapy) for a patient with iron deficiency?

Ferric Carboxymaltose Dosing for Iron Deficiency

For patients weighing ≥50 kg with iron deficiency anemia, administer ferric carboxymaltose 750 mg intravenously in two doses separated by at least 7 days for a total cumulative dose of 1,500 mg per course, or alternatively, a single dose of up to 1,000 mg can be given. 1

Standard Dosing Regimens

For Iron Deficiency Anemia (General Population)

Patients ≥50 kg:

• Standard regimen: 750 mg IV × 2 doses, separated by ≥7 days (total 1,500 mg per course) 1
• Alternative single-dose regimen: 15 mg/kg up to maximum 1,000 mg IV as single dose per course 1

Patients <50 kg:

• 15 mg/kg IV in two doses separated by ≥7 days per course 1

For Heart Failure with Iron Deficiency

The dosing differs based on weight and hemoglobin levels 1:

Patients <70 kg:

• Hb <10 g/dL: 1,000 mg on Day 1, then 500 mg at Week 6 1
• Hb 10-14 g/dL: 1,000 mg on Day 1 only 1
• Hb >14 to <15 g/dL: 500 mg on Day 1 only 1

Patients ≥70 kg:

• Hb <10 g/dL: 1,000 mg on Day 1, then 1,000 mg at Week 6 1
• Hb 10-14 g/dL: 1,000 mg on Day 1, then 500 mg at Week 6 1
• Hb >14 to <15 g/dL: 500 mg on Day 1 only 1

Maintenance dosing for heart failure: Administer 500 mg at 12,24, and 36 weeks if serum ferritin <100 ng/mL or ferritin 100-300 ng/mL with transferrin saturation <20% 1

Administration Methods

Two acceptable administration routes exist:

1. Undiluted slow IV push: Administer at approximately 100 mg (2 mL) per minute for 500-750 mg doses; for 1,000 mg doses, administer over 15 minutes 1

2. IV infusion: Dilute up to 1,000 mg in no more than 250 mL of 0.9% sodium chloride (concentration ≥2 mg iron/mL) and infuse over at least 15 minutes 1, 2

The American Journal of Hematology recommends dilution in 100 mL normal saline infused over 20-30 minutes 2, though the FDA label allows for larger dilution volumes 1.

Clinical Efficacy Timeline

Expected hemoglobin response:

• Reticulocytosis occurs at 3-5 days post-administration 3
• Mean hemoglobin increase of 8 g/L over 8 days following single dose of 15 mg/kg (max 1,000 mg) 3, 2
• Hemoglobin should increase within 1-2 weeks and by 1-2 g/dL within 4-8 weeks 2

Monitoring Requirements

Immediate post-infusion:

• Observe patients for at least 30 minutes following each IV injection for adverse effects 2, 1
• Monitor for extravasation, as brown discoloration may be long-lasting 1

Follow-up laboratory evaluation:

• Check CBC and iron parameters (ferritin, transferrin saturation) 4-8 weeks after the last infusion 2
• Critical caveat: Do NOT evaluate iron parameters within 4 weeks of administration, as circulating iron interferes with assays leading to inaccurate results 2
• For heart failure patients, re-evaluate iron status at 3 months 2, 4

Contraindications and Safety Considerations

Absolute contraindications:

• Hypersensitivity to ferric carboxymaltose or its excipients 2, 1
• Known serious hypersensitivity to other parenteral iron products 2, 1
• Anemia not attributed to iron deficiency 2, 1
• Evidence of iron overload 2, 1
• Hemoglobin >15 g/dL 2

Use with caution in:

• Acute or chronic infection (stop treatment in patients with bacteremia) 2, 4
• Known drug allergies, especially severe asthma, eczema, or atopic allergies 2, 4
• Patients requiring repeat infusions within 3 months 2

Critical Safety Warning: Hypophosphatemia

Ferric carboxymaltose has significantly higher rates of hypophosphatemia (58%) compared to iron derisomaltose (4%) or iron sucrose (1%). 2 Most cases are biochemically moderate (serum phosphate 0.32-0.64 mmol/L) and asymptomatic, resolving without intervention 2. However, check serum phosphate levels in patients at risk for low serum phosphate who require repeat courses or any patient receiving repeat treatment within 3 months 1. This is a major distinguishing factor when choosing between IV iron formulations for patients requiring repeated dosing.

Repeat Treatment

Ferric carboxymaltose treatment may be repeated if iron deficiency anemia or iron deficiency in heart failure recurs 1. The typical total dose of 1,000-1,500 mg usually restores iron stores to normal 3. For patients with ongoing losses (inflammatory bowel disease, heavy menstrual bleeding), periodic monitoring every 6 months initially is recommended to detect recurrent iron deficiency 2.