Treatment of Iron Deficiency Anemia

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

Initial Oral Iron Therapy

Ferrous sulfate 200 mg once daily is the standard first-line treatment, providing 65 mg of elemental iron per dose 1, 2
Once-daily dosing is superior to multiple daily doses because it improves tolerability while maintaining equal effectiveness 1
Take iron on an empty stomach for optimal absorption, though taking with food is acceptable if gastrointestinal side effects occur 1
Add vitamin C (ascorbic acid) 500 mg with each iron dose to enhance absorption, particularly when response is suboptimal 1
Alternative formulations (ferrous gluconate or ferrous fumarate) are equally effective if ferrous sulfate is not tolerated 1

Hemoglobin should rise by approximately 2 g/dL after 3-4 weeks of treatment 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
If no response occurs within 4 weeks, assess for non-adherence, malabsorption, or ongoing blood loss 1

Use intravenous iron when oral iron fails or is contraindicated based on these specific criteria: 3, 1

Intolerance to at least two different oral iron preparations 1
Inflammatory bowel disease with active inflammation, especially if hemoglobin <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
Inadequate response to oral iron therapy after 4 weeks 1

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

Determine whether iron deficiency is due to inadequate intake/absorption or 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

Use intravenous iron therapy in patients who have undergone bariatric procedures that disrupt normal duodenal iron absorption 3
This applies particularly to procedures likely to affect the duodenum 3

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
Progress to intravenous iron therapy if iron stores do not improve with oral supplementation 3

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

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

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 use multiple daily doses—once-daily dosing is better tolerated with similar efficacy 1
Do not stop iron therapy when hemoglobin normalizes—continue for 3 months to replenish stores 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 1

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