What is the treatment for iron deficiency anemia?

Treatment of Iron Deficiency Anemia

Start with oral ferrous sulfate 200 mg (65 mg elemental iron) once daily, which is the preferred first-line treatment due to its effectiveness and low cost. 1

First-Line Oral Iron Therapy

• Ferrous sulfate 200 mg once daily is the recommended formulation rather than multiple daily doses, as once-daily dosing improves tolerability while maintaining equal or better effectiveness 1
• Each 324 mg tablet of ferrous sulfate contains 65 mg of elemental iron 2
• Alternative oral formulations (ferrous gluconate or ferrous fumarate) are equally effective if ferrous sulfate is not tolerated, though they offer no therapeutic advantage and are typically more expensive 1
• Add vitamin C (ascorbic acid) 500 mg with each iron dose to enhance absorption, particularly when response is poor 1
• Take iron on an empty stomach for optimal absorption, though taking with food is acceptable if gastrointestinal side effects occur 1

Expected Response and Monitoring

• Hemoglobin should rise by approximately 2 g/dL after 3-4 weeks of treatment 1
• If no response occurs within 4 weeks, assess for non-adherence, malabsorption, or ongoing blood loss 1
• Continue oral iron therapy for 3 months after hemoglobin normalizes to fully replenish iron stores 1
• Monitor hemoglobin and red cell indices every 3 months for the first year, then again after another year 1

When to Switch to Intravenous Iron

Intravenous iron should be used when oral iron fails or is contraindicated, with specific indications including:

• Intolerance to at least two different oral iron preparations 3, 1
• Inadequate response to oral iron therapy after 4 weeks 3, 1
• Inflammatory bowel disease with active inflammation, especially if hemoglobin is less than 10 g/dL 3, 1
• Post-bariatric surgery patients with disrupted duodenal iron absorption 3, 1
• Celiac disease with inadequate response to oral iron despite gluten-free diet adherence 3, 1
• Ongoing gastrointestinal blood loss exceeding oral replacement capacity 1

Intravenous Iron Formulations

• Prefer IV iron formulations that can replace iron deficits with 1-2 infusions rather than multiple infusions 3, 1
• All intravenous iron formulations have similar risks; true anaphylaxis is very rare (less than 1%) 3, 4
• The vast majority of reactions to intravenous iron are complement activation-related pseudo-allergy (infusion reactions) and should be treated as such 3

Special Population Considerations

Inflammatory Bowel Disease

• Determine whether iron deficiency anemia is due to inadequate intake/absorption or loss of iron from gastrointestinal bleeding 3
• Treat active inflammation effectively to enhance iron absorption or reduce iron depletion 3
• Use intravenous iron in patients with active inflammation and compromised absorption 3

Post-Bariatric Surgery

• Intravenous iron therapy should be used in individuals who have undergone bariatric procedures that disrupt normal duodenal iron absorption 3

Celiac Disease

• Ensure adherence to a gluten-free diet to improve iron absorption 3
• Consider oral iron supplementation based on severity of iron deficiency and patient tolerance 3
• Use intravenous iron therapy if iron stores do not improve with oral supplementation 3

Portal Hypertensive Gastropathy

• Use oral iron supplements initially to replenish iron stores 3
• Switch to intravenous iron therapy in patients with ongoing bleeding who do not respond to oral iron therapy 3
• Consider treatment of portal hypertension with nonselective β-blockers if no other source of chronic blood loss is identified 3

Gastric Antral Vascular Ectasia

• If inadequate response to iron replacement occurs, consider endoscopic therapy with endoscopic band ligation or thermal methods such as argon plasma coagulation 3

Common Pitfalls to Avoid

• Do not prescribe multiple daily doses of oral iron - this increases side effects without improving efficacy 1
• Do not stop iron therapy when hemoglobin normalizes - continue for 3 months to replenish stores 1
• Do not continue oral iron indefinitely without response - reassess after 4 weeks and switch to IV iron if hemoglobin fails to rise 1
• Do not overlook vitamin C supplementation when oral iron response is suboptimal 1
• Do not fail to identify and treat the underlying cause of iron deficiency while supplementing iron 1

Failure to Respond

• If anemia does not resolve within 6 months despite appropriate iron therapy, reassess for ongoing blood loss 1
• Evaluate for malabsorption syndromes 1
• Consider further gastrointestinal investigation 1
• Verify patient adherence to therapy 1