When are iron infusions recommended for patients with iron deficiency anemia?

When to Use Iron Infusions for Iron Deficiency Anemia

Intravenous iron should be used if the patient does not tolerate oral iron, ferritin levels do not improve with a trial of oral iron, or the patient has a condition in which oral iron is not likely to be absorbed. 1

First-Line Treatment: Oral Iron

Oral iron supplementation remains the first-line therapy for most patients with iron deficiency anemia due to its:

• Simplicity and low cost - ferrous sulfate 200 mg twice daily is the most economical option 1
• Effectiveness in replenishing iron stores when taken for 3 months after correction of deficiency 1
• Safety profile with minimal serious adverse effects 1
• Ability to be modified for better tolerance - lower doses or alternative formulations (ferrous fumarate, ferrous gluconate) may be better tolerated 1
• Option for every-other-day dosing which may improve tolerance while maintaining effectiveness 1
• Enhanced absorption when combined with vitamin C (250-500 mg twice daily) 1

Indications for Intravenous Iron

IV iron is indicated in the following situations:

• Intolerance to oral iron therapy (gastrointestinal side effects) 1
• Inadequate response to oral iron despite good adherence 1
• Conditions where oral iron absorption is impaired:
  • Active inflammatory bowel disease with inflammation 1
  • Post-bariatric surgery, particularly procedures affecting duodenal absorption 1
  • Celiac disease with ongoing malabsorption 1
• Severe or symptomatic anemia requiring rapid correction 2
• Ongoing blood loss exceeding intestinal absorption capacity 1
• Functional iron deficiency in chronic kidney disease patients on erythropoietin therapy 1
• Portal hypertensive gastropathy with ongoing bleeding unresponsive to oral iron 1

IV Iron Formulation Selection

When choosing an IV iron formulation:

• Formulations that can replace iron deficits with 1-2 infusions are preferred over those requiring multiple infusions 1
• Available options include:
  • Ferric carboxymaltose (Injectafer): Can deliver up to 1000 mg in a single dose over 15 minutes 2
  • Iron sucrose (Venofer): Typically 200 mg per dose over 10 minutes 1
  • Iron dextran (Cosmofer): Can provide complete replacement in a single infusion but carries higher risk of serious reactions 1

Safety Considerations

• All IV iron formulations carry similar risks, but true anaphylaxis is very rare 1
• Most reactions are complement activation-related pseudo-allergy (infusion reactions) 1
• Resuscitation facilities should be available when administering IV iron 1
• Patients should be monitored for 60 minutes after initial infusion of IV iron 1
• Monitor for hypophosphatemia in patients requiring repeat courses of treatment 2

Special Patient Populations

Inflammatory Bowel Disease

• Determine if anemia is due to inadequate intake/absorption or blood loss 1
• Treat active inflammation to enhance iron absorption 1
• Use IV iron when active inflammation compromises absorption 1

Chronic Kidney Disease

• IV iron is preferred in hemodialysis patients 1
• Consider IV iron when TSAT ≤20% and ferritin ≤100 ng/mL 1
• Address all correctable causes of anemia before initiating ESA therapy 1

Post-Bariatric Surgery

• IV iron is recommended for patients with iron deficiency anemia after bariatric procedures that disrupt duodenal absorption 1

Portal Hypertensive Gastropathy

• Start with oral iron supplements 1
• Switch to IV iron if ongoing bleeding causes inadequate response 1
• Consider treating portal hypertension with non-selective β-blockers 1

Follow-up Monitoring

• After normalization, monitor hemoglobin and red cell indices every 3 months for 1 year, then after another year 1
• Provide additional oral iron if hemoglobin or red cell indices fall below normal 1
• Further investigation is only necessary if hemoglobin cannot be maintained with supplementation 1