What are the guidelines for iron transfusion in patients with iron deficiency?

Iron Transfusion Guidelines for Iron Deficiency

Intravenous iron therapy is recommended for patients with iron deficiency who have intolerance or unresponsiveness to oral iron, when rapid correction of iron deficit is required, or in patients with chronic inflammatory conditions. 1

Diagnosis of Iron Deficiency

Iron deficiency should be assessed before initiating treatment:

• Absolute iron deficiency: Serum ferritin <30 ng/mL in patients without inflammatory conditions 2
• Functional iron deficiency: Serum ferritin ≤800 ng/mL with transferrin saturation <20% 3
• Assessment frequency: Every 1-3 months in patients requiring iron/ESA therapy; can be less frequent (yearly) in stable patients with mild anemia 3

Route of Administration Decision Algorithm

Oral Iron First-Line Therapy for:

• Patients with absolute iron deficiency (ferritin <100 ng/mL) and non-inflammatory conditions (CRP <5 mg/L) 3
• Non-dialysis CKD patients as initial therapy 3
• Stable patients without urgent need for iron repletion 1

Intravenous Iron Indicated for:

1. Intolerance to oral iron 1, 2
2. Unresponsiveness to oral iron (Hb increase <1 g/dL after trial) 4
3. Need for rapid correction of iron deficit 5
4. Impaired iron absorption:
   • Celiac disease
   • Post-bariatric surgery
   • Atrophic gastritis 2
5. Chronic inflammatory conditions:
   • Cancer patients 3
   • Chronic kidney disease 3
   • Heart failure 3, 2
   • Inflammatory bowel disease 2
6. Ongoing blood loss 2
7. During second and third trimesters of pregnancy 2

Intravenous Iron Dosing

For General Iron Deficiency:

• For patients ≥50 kg: 750 mg IV in two doses separated by at least 7 days (total 1,500 mg) or single dose of 15 mg/kg up to 1,000 mg 6
• For patients <50 kg: 15 mg/kg IV in two doses separated by at least 7 days 6

For Iron Deficiency with Heart Failure:

Weight-based and hemoglobin-based dosing 6:

• <70 kg:
  • Hb <10 g/dL: 1,000 mg on day 1
  • Hb 10-14 g/dL: 1,000 mg on day 1
  • Hb >14 to <15 g/dL: 500 mg on day 1
• ≥70 kg:
  • Hb <10 g/dL: 1,000 mg on day 1,000 mg at week 6
  • Hb 10-14 g/dL: 1,000 mg on day 1,500 mg at week 6
  • Hb >14 to <15 g/dL: 500 mg on day 1

Maintenance dose of 500 mg at weeks 12,24, and 36 if serum ferritin <100 ng/mL or serum ferritin 100-300 ng/mL with transferrin saturation <20% 6

Available IV Iron Formulations

• Ferric carboxymaltose: Up to 1,000 mg in 15 minutes 3, 6
• Iron sucrose: 200-500 mg, infusion time 30-210 minutes 3
• Ferric gluconate: Maximum 125 mg, infusion time 60 minutes 3
• Iron dextran: Variable dosing, infusion time 240-360 minutes 3
• Iron isomaltoside: Up to 1,000 mg (20 mg/kg), infusion time 15 minutes 3

Safety Considerations

Potential Adverse Events:

• Infusion reactions (anaphylactoid reactions, hypotension, shortness of breath, chills) 3
• Hypophosphatemia (especially with ferric carboxymaltose, affecting 50-74% of patients) 5
• Increased risk of thrombotic events 3
• Potential increased risk of infections (use with caution in patients with active infection) 3

Monitoring:

• Check serum phosphate levels in patients requiring repeat courses of treatment 6
• Wait 24-48 hours after iron sucrose or iron gluconate administration before measuring iron status 3
• For iron dextran, wait 1-2 weeks after 100-500 mg doses before assessing iron status 3

Clinical Efficacy

• IV iron is superior to oral iron in increasing hemoglobin levels in patients with inadequate response to oral iron 4
• IV iron reduces the need for RBC transfusions 3
• IV iron increases response to erythropoiesis-stimulating agents (ESAs) 3

By following these guidelines, clinicians can effectively manage iron deficiency while minimizing risks associated with iron therapy.