What is the recommended treatment regimen for iron deficiency anemia using Ferrous carboxymaltose (Intravenous iron replacement therapy)?

Ferric Carboxymaltose Treatment Regimen for Iron Deficiency Anemia

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 15 mg/kg up to a maximum of 1,000 mg as a single dose. 1

Dosing by Patient Weight and Hemoglobin

For Patients ≥50 kg:

• Standard regimen: 750 mg IV on Day 1 and Day 7-14 (total 1,500 mg per course) 1
• Alternative single-dose regimen: 15 mg/kg up to maximum 1,000 mg IV as single dose 1
• Infusion time: 15 minutes minimum for doses up to 1,000 mg 1

For Patients <50 kg:

• Dosing: 15 mg/kg body weight IV in two doses separated by at least 7 days 1

For Patients with Heart Failure and Iron Deficiency:

The dosing differs based on weight and hemoglobin levels 1:

Weight <70 kg:

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

Weight ≥70 kg:

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

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

Administration Methods

Two acceptable routes 1:

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

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

Clinical Indications for IV Iron Over Oral

Ferric carboxymaltose should be first-line treatment in 2:

• Clinically active inflammatory bowel disease
• Previous intolerance to oral iron
• Hemoglobin <10 g/dL
• Patients requiring erythropoiesis-stimulating agents 2

The rationale is that oral iron has limited absorption and causes significant gastrointestinal side effects (26.2% treatment-related adverse events with oral iron vs 2.7% with ferric carboxymaltose) 3. Intravenous iron achieves more rapid hemoglobin correction and complete iron store repletion compared to oral formulations 4.

Expected Response and Monitoring

Hemoglobin Response:

• Initial increase: Within 1-2 weeks of treatment 5
• Target increase: 1-2 g/dL within 4-8 weeks 5
• Acceptable response: At least 2 g/dL increase within 4 weeks 2
• Peak response: Mean increase of 0.95 g/dL by Day 42 (vs 0.50 g/dL with oral iron) 3

Iron Store Repletion:

• Ferritin increase: Mean 432 ng/mL increase by Day 42 (vs 18 ng/mL with oral iron) 3
• Transferrin saturation: Mean 13.6% increase by Day 42 (vs 6.1% with oral iron) 3

Follow-up Timing:

• Do not check iron parameters within 4 weeks of IV administration, as ferritin levels are markedly elevated immediately post-infusion and circulating iron interferes with assay results 6, 5
• First reassessment: 4-8 weeks post-treatment with CBC and iron parameters (ferritin, transferrin saturation) 5
• Optimal timing: 3 months after initial treatment 6
• Long-term monitoring: Every 3 months for first year, then 6-12 months thereafter 5

Repeat Treatment Criteria

Initiate repeat treatment when 4:

• Ferritin drops below 100 ng/mL, OR
• Hemoglobin falls below 12 g/dL (women) or 13 g/dL (men) 5

For repeat courses within 3 months: Check serum phosphate levels before retreatment 1

Critical Safety Considerations

Contraindications 1:

• Hypersensitivity to ferric carboxymaltose or excipients
• Known serious hypersensitivity to other parenteral iron products
• Anemia not attributed to iron deficiency
• Evidence of iron overload

Monitoring Requirements:

• Observe patient for at least 30 minutes after administration for allergic reactions 1
• Monitor for extravasation during infusion; brown discoloration at extravasation site may be long-lasting 1
• Check serum phosphate in patients requiring repeat courses, especially if within 3 months 1

Hypophosphatemia Risk:

Transient, asymptomatic hypophosphatemia is the most common laboratory abnormality, particularly with repeated dosing 7. This can lead to serious complications including bone softening and fractures with multiple treatments 1. Monitor phosphate levels and treat as medically indicated 1.

Blood Pressure Monitoring:

High blood pressure with facial flushing, dizziness, or nausea can occur during treatment 1. Check blood pressure after administration 1.

Advantages Over Other IV Iron Preparations

Ferric carboxymaltose offers distinct advantages 2:

• Higher single dose: 1,000 mg vs 200 mg for iron sucrose 2
• Shorter infusion time: 15 minutes vs 6 hours for iron dextran 2
• No test dose required: Unlike iron dextran 8
• Fewer total infusions needed: Up to 2 FCM infusions vs 3-5 of iron sucrose to reach target 9
• Lower anaphylaxis risk: No anaphylaxis reported in initial trials (vs 0.6-0.7% with iron dextran) 2

The cost per gram is higher (£217.50 vs £70.80 for iron sucrose) 2, but fewer administrations make it cost-effective overall 10, 7.

Common Pitfalls to Avoid

1. Do not administer if hemoglobin >15 g/dL 5
2. Avoid dilution below 2 mg iron/mL to maintain stability 1
3. Do not evaluate iron parameters within first 4 weeks post-administration 6, 5
4. Use caution in active infection; stop treatment in patients with bacteremia 6
5. Monitor for hypophosphatemia with repeat dosing, especially in patients with inflammatory bowel disease, hyperparathyroidism, or vitamin D deficiency 1