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, 2
Initial Oral Iron Therapy
- Ferrous sulfate 200 mg once daily is the recommended formulation rather than three-times-daily dosing, as once-daily or alternate-day dosing improves tolerability while maintaining effectiveness 1, 2
- Alternative oral formulations (ferrous gluconate, ferrous fumarate) are equally effective if ferrous sulfate is not tolerated 1, 2
- Add vitamin C (ascorbic acid) supplementation when response to oral iron is poor, as it enhances iron absorption 1, 2
- Continue oral iron therapy for 3 months after anemia correction to fully replenish iron stores 1, 2
Expected Response and Monitoring
- Hemoglobin should rise by approximately 2 g/dL after 3-4 weeks of treatment 1, 2
- If no response occurs within 4 weeks, assess for non-adherence, malabsorption, or ongoing blood loss 1
- Monitor hemoglobin and red cell indices every 3 months for the first year, then again after another year 1, 2
When to Switch to Intravenous Iron
Intravenous iron should be used when oral iron fails or is contraindicated. 1, 2 Specific indications include:
Absolute Indications for IV Iron
- Intolerance to at least two different oral iron preparations 1, 2
- Inflammatory bowel disease with active inflammation (especially if hemoglobin <10 g/dL) 1, 2
- Post-bariatric surgery patients with disrupted duodenal iron absorption 1
- Celiac disease with inadequate response to oral iron despite gluten-free diet adherence 1, 2
- Ongoing gastrointestinal blood loss exceeding oral replacement capacity (e.g., portal hypertensive gastropathy, gastric antral vascular ectasia) 1
- Pregnancy during second and third trimesters when oral iron is insufficient 2, 3
IV Iron Formulations
- Prefer IV iron formulations that can replace iron deficits with 1-2 infusions 2
- Iron dextran can be given as total dose infusion but carries higher anaphylaxis risk 1
- Most infusion reactions are complement activation-related pseudo-allergy (not true anaphylaxis) and should be treated accordingly 1
Special Population Considerations
Inflammatory Bowel Disease
- Treat active inflammation first to enhance iron absorption and reduce iron depletion 1
- Use IV iron as first-line therapy when hemoglobin <10 g/dL with active disease 2
Portal Hypertensive Gastropathy
- Start with oral iron supplementation initially 1
- Switch to IV iron if ongoing bleeding persists without response to oral therapy 1
- Consider nonselective β-blockers to treat underlying portal hypertension 1
Celiac Disease
- Ensure strict adherence to gluten-free diet to improve iron absorption 1, 2
- Progress to IV iron if oral supplementation fails despite dietary compliance 1, 2
Post-Bariatric Surgery
- IV iron is preferred due to disrupted duodenal absorption mechanisms 1
Common Pitfalls to Avoid
- Do not continue oral iron indefinitely without response - reassess after 4 weeks and switch to IV iron if hemoglobin fails to rise 1, 2
- Do not use multiple daily doses - once-daily or alternate-day dosing is better tolerated with similar efficacy 1, 2
- Do not stop iron therapy when hemoglobin normalizes - continue for 3 months to replenish stores 1, 2
- Do not overlook vitamin C supplementation when oral iron response is suboptimal 1, 2
- Do not fail to identify and treat the underlying cause of iron deficiency while supplementing 1, 2
- Do not use parenteral iron as first-line unless specific contraindications to oral therapy exist 1, 4
Failure to Respond
If anemia does not resolve within 6 months despite appropriate iron therapy: 2
- Reassess for ongoing blood loss
- Evaluate for malabsorption syndromes
- Consider further gastrointestinal investigation
- Verify patient adherence to therapy