What is the recommended intravenous iron infusion dose?

Recommended Intravenous Iron Infusion Dose

For iron deficiency anemia in adults weighing ≥50 kg, administer a total cumulative dose of 1,500 mg of IV iron, given as two 750 mg doses separated by at least 7 days, which is the FDA-approved regimen for ferric carboxymaltose and reflects the actual iron deficit in most patients. 1, 2

Standard Dosing by Body Weight

Adults ≥50 kg

• Total dose: 1,500 mg divided as 750 mg × 2 doses separated by ≥7 days 1
• Alternative single-dose option: 15 mg/kg (maximum 1,000 mg) as a single infusion 1
• Clinical evidence strongly supports 1,500 mg over 1,000 mg: Studies using the modified Ganzoni formula calculated the average iron deficit at 1,531 mg, and patients receiving only 1,000 mg required significantly more retreatment (11.1% vs 5.6%, p<0.001) compared to those receiving 1,500 mg 2

Adults <50 kg

• Dose: 15 mg/kg body weight divided into two doses separated by ≥7 days 1

Pediatric Patients (≥1 year old)

• Dose: 15 mg/kg body weight divided into two doses separated by ≥7 days 1
• For hemodialysis patients on iron sucrose: <10 kg = 25 mg/dose; 10-20 kg = 50 mg/dose; >20 kg = 100 mg/dose 3

Formulation-Specific Dosing Regimens

Ferric Carboxymaltose (Injectafer)

• Preferred for rapid repletion: 750 mg IV over ≥15 minutes, repeated after 7 days (total 1,500 mg) 1
• Can administer up to 1,000 mg as single dose over 15 minutes 1
• No test dose required 1

Iron Sucrose

• Maximum safe single dose: 300 mg over 2 hours 4
• Standard dosing: 200 mg per administration as IV push over 10 minutes, repeated until total calculated dose achieved 3
• Doses of 400-500 mg cause unacceptable adverse event rates (hypotension, nausea, back pain) and should be avoided 4
• For hemodialysis patients: 100-200 mg directly into dialysis line 2-3 times weekly 3

Low Molecular Weight Iron Dextran

• Total dose infusion: 500-1,000 mg diluted in 250 mL normal saline over 1 hour 5
• Mandatory 25 mg test dose via slow IV push with 1-hour observation before therapeutic dose 5
• Can repeat as needed for maintenance 5
• Never use high molecular weight iron dextran due to anaphylaxis risk 5

Ferumoxytol

• Total dose: 1,020 mg can be safely administered over 15 minutes as single infusion 6
• Demonstrated excellent efficacy with mean hemoglobin increase of 2.1 g/dL at 4 weeks and 2.6 g/dL at 8 weeks 6

Special Population Dosing

Cancer Patients with Anemia

• Total dose: 1,000 mg of iron for those receiving erythropoiesis-stimulating agents (ESAs) 7
• Doses ranging from 937.5-2,000 mg have been studied, with 1,000 mg being most common 7
• Total dose infusion as effective as multiple low-dose infusions but more convenient 7

Inflammatory Bowel Disease Patients

Simple dosing scheme (preferred over Ganzoni formula): 7

• Hemoglobin 10-12 g/dL (women) or 10-13 g/dL (men):
  • Body weight <70 kg: 1,000 mg
  • Body weight ≥70 kg: 1,500 mg
• Hemoglobin 7-10 g/dL:
  • Body weight <70 kg: 1,500 mg
  • Body weight ≥70 kg: 2,000 mg

Heart Failure Patients (NYHA Class II/III)

Initial dosing based on weight and hemoglobin: 1

• Weight <70 kg: 1,000 mg (Day 1), then 500 mg (Week 6) if Hb <14 g/dL
• Weight ≥70 kg: 1,000 mg (Day 1), then 1,000 mg (Week 6) if Hb <10 g/dL; 500 mg if Hb 10-14 g/dL
• Maintenance: 500 mg at 12,24, and 36 weeks if ferritin <100 ng/mL or ferritin 100-300 ng/mL with TSAT <20% 1

Administration Guidelines

Preparation and Infusion Rates

• Ferric carboxymaltose: Dilute up to 1,000 mg in ≤250 mL normal saline (concentration ≥2 mg/mL), infuse over ≥15 minutes 1
• IV push option: 100 mg per minute for doses ≤750 mg; 1,000 mg must be given over 15 minutes 1
• Iron sucrose: 200 mg as IV push over 10 minutes 3
• Iron dextran: 500-1,000 mg in 250 mL normal saline over 1 hour 5

Critical Safety Monitoring

• Observe all patients for ≥30 minutes post-infusion for hypersensitivity reactions 7, 8
• Staff must be trained to recognize and manage anaphylactic/anaphylactoid reactions 7
• Resuscitation facilities must be immediately available 7, 3
• Do not administer during active infection or bacteremia 5, 8

Laboratory Monitoring and Retreatment

Timing of Iron Parameter Assessment

• Wait 4-8 weeks after last infusion before measuring hemoglobin, TSAT, and ferritin 3
• For doses ≥1,000 mg: wait minimum 2 weeks before checking iron parameters 5, 8
• For weekly doses of 100-125 mg: can measure without interrupting therapy 8

Target Parameters

• Hemoglobin increase of 1-2 g/dL within 4-8 weeks is expected 3
• Target TSAT >20%, ferritin >100 ng/mL 5
• Withhold IV iron if: TSAT >50% or ferritin >800 ng/mL 7, 3, 5

Retreatment Criteria

• May repeat if iron deficiency anemia recurs 1
• Check serum phosphate in patients requiring repeat course within 3 months 1
• For maintenance in hemodialysis: 25-125 mg weekly once targets achieved 8

Common Pitfalls to Avoid

• Underdosing: 1,000 mg is insufficient for complete iron repletion in most patients; 1,500 mg is closer to actual deficit 2
• Checking labs too early: Iron parameters measured <2 weeks after large doses (≥1,000 mg) will be inaccurate 5, 8
• Exceeding safe single doses: Iron sucrose doses >300 mg cause excessive adverse events 4
• Skipping test dose for iron dextran: The 25 mg test dose is mandatory despite low anaphylaxis rates 5
• Administering during infection: Active infection is an absolute contraindication 5, 8
• Misinterpreting arthralgias/myalgias: These are common dose-related effects with larger doses (>500 mg), not anaphylaxis, and resolve spontaneously 5