What are the recommended dosages for intravenous (IV) iron supplementation?

IV Iron Dosing Recommendations

For most patients requiring IV iron, the specific dosage and administration protocol depends on the iron formulation used, with ferric carboxymaltose allowing up to 1,500 mg total dose, while older preparations like ferric gluconate and iron sucrose are limited to lower individual doses of 125 mg and 200-300 mg respectively. 1, 2, 3

Iron Preparation Selection and Dosing by Formulation

Ferric Carboxymaltose (Preferred for Rapid Repletion)

For patients ≥50 kg with iron deficiency anemia:

• 750 mg IV in two doses separated by at least 7 days (total 1,500 mg per course) 1
• Alternative: Single dose of 15 mg/kg up to maximum 1,000 mg 1

For patients <50 kg:

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

Administration method:

• Can be given undiluted as slow IV push over 15 minutes for 1,000 mg dose 1
• Or diluted in up to 250 mL sterile 0.9% saline (minimum concentration 2 mg iron/mL) infused over at least 15 minutes 1

Iron Dextran (Low-Molecular-Weight INFeD Preferred)

Test dose required: 25 mg slow IV push, wait 1 hour before main dose 2, 3

Standard dosing for hemodialysis patients:

• 100 mg IV over 5 minutes OR as IV push over 2 minutes 2, 4
• Repeated weekly for 10 doses to achieve total 1,000 mg 2, 3
• Maximum total dose: 1,000 mg 2, 3

For CKD, home hemodialysis, or peritoneal dialysis patients:

• 500-1,000 mg diluted in 250 mL normal saline infused over 1 hour 2, 4
• Can repeat as needed to maintain iron stores 2

Avoid high-molecular-weight iron dextran (Dexferrum) due to higher adverse event rates 2, 3

Ferric Gluconate (Ferrlecit)

Test dose: 25 mg slow IV push or infusion at physician discretion (strongly recommended for patients with previous sensitivities) 2, 3, 5

Adult dosing:

• 125 mg IV over 60 minutes (diluted in 100 mL 0.9% saline) 2, 3, 5
• OR undiluted as slow IV injection at rate up to 12.5 mg/min 5
• Repeated weekly for 8 doses 2, 3
• Individual doses above 125 mg are NOT recommended 2, 3
• Maximum total dose: 1,000 mg 2, 3

Iron Sucrose

Test dose: 25 mg slow IV push at physician discretion (strongly recommended for patients with previous sensitivities) 2, 3

Dosing:

• 200 mg IV over 60 minutes 2, 3
• Repeated every 2-3 weeks 2, 3
• Individual doses above 300 mg are NOT recommended 2, 3
• Research demonstrates 400-500 mg doses have unacceptably high adverse event rates (hypotension, nausea, back pain) 6

Pediatric Dosing (Age ≥6 Years)

Ferric Gluconate for Hemodialysis Patients:

• 0.12 mL/kg (1.5 mg/kg elemental iron) diluted in 25 mL 0.9% saline, infused over 1 hour 5

Iron Dextran for Hemodialysis (10-dose course):

• Weight ≤10 kg: 25 mg per dose 3, 4
• Weight 10-20 kg: 50 mg per dose 3, 4
• Weight ≥20 kg: 100 mg per dose 3, 4

Iron Dextran for Predialysis/Peritoneal Dialysis:

• Weight ≤10 kg: 125 mg in 75 mL saline 3, 4
• Weight 10-20 kg: 250 mg in 125 mL saline 3, 4
• Weight ≥20 kg: 500 mg in 250 mL saline 3, 4

Special Population: Heart Failure with Iron Deficiency

Ferric carboxymaltose dosing based on weight and hemoglobin 1:

Weight <70 kg:

• Hb <10 g/dL: 1,000 mg Day 1,500 mg Week 6
• Hb 10-14 g/dL: 1,000 mg Day 1, no Week 6 dose
• Hb >14 to <15 g/dL: 500 mg Day 1, no Week 6 dose

Weight ≥70 kg:

• Hb <10 g/dL: 1,000 mg Day 1,000 mg Week 6
• Hb 10-14 g/dL: 1,000 mg Day 1,500 mg Week 6
• Hb >14 to <15 g/dL: 500 mg Day 1, no Week 6 dose

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

Evidence-Based Total Dose Considerations

Research demonstrates that 1,000 mg total cumulative dose is insufficient for most patients with iron deficiency anemia 7. Analysis of multiple clinical studies calculated average iron deficit at 1,392-1,531 mg 7. Patients receiving 1,500 mg ferric carboxymaltose had significantly lower retreatment rates (5.6%) compared to those receiving 1,000 mg iron sucrose (11.1%, p<0.001) 7.

Monitoring and Laboratory Timing

Target iron parameters:

• TSAT ≥20% and serum ferritin ≥100 ng/mL 3, 4

Timing of iron parameter measurement:

• Doses ≤125 mg weekly: Can measure without interrupting therapy 4
• Doses 200-500 mg: Wait at least 7 days 4
• Doses ≥1,000 mg: Wait at least 14 days 4
• Monitor every 3 months during maintenance phase 3

Avoid iron overload: Do not administer if TSAT >50% and/or ferritin >800 ng/mL 4, 8

Critical Safety Considerations

Absolute contraindications:

• Active infection 2, 3
• Known hypersensitivity to the specific iron preparation 5
• Iron overload 4

Common adverse events include hypotension, hypertension, nausea, vomiting, diarrhea, pain, fever, dyspnea, pruritus, headaches, and dizziness 2, 3. Monitor patients for at least 30 minutes after administration and ensure resuscitation equipment is immediately available 5.

Avoid extravasation as brown discoloration may be long-lasting; discontinue infusion immediately if extravasation occurs 1.