Treatment of Iron Deficiency
Start with oral ferrous sulfate 200 mg once daily, which is the most effective, evidence-based, and cost-efficient first-line treatment for iron deficiency. 1
Initial Oral Iron Therapy
Ferrous sulfate 200 mg once daily is the gold standard treatment, preferred over multiple daily dosing because it maintains effectiveness while significantly improving gastrointestinal tolerability. 1, 2 Each 324 mg tablet of ferrous sulfate contains 65 mg of elemental iron. 3
Key Implementation Points:
Take on an empty stomach for optimal absorption, though taking with food is acceptable if gastrointestinal side effects occur. 1
Add vitamin C (ascorbic acid) 250-500 mg with each iron dose to enhance absorption, particularly when response is suboptimal. 4, 1
Continue therapy for 3 months after hemoglobin normalizes to fully replenish iron stores—stopping early is a critical error. 4, 1
Alternative formulations (ferrous gluconate or ferrous fumarate) are equally effective if ferrous sulfate is not tolerated. 4, 1
Expected Response:
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
When to Switch to Intravenous Iron
Intravenous iron is indicated when oral therapy fails or specific contraindications exist. 1 The specific indications are:
Intolerance to at least two different oral iron preparations 4, 1
Inflammatory bowel disease with active inflammation, especially if hemoglobin <10 g/dL 1
Post-bariatric surgery patients due to disrupted duodenal absorption 1
Celiac disease with inadequate response to oral iron despite gluten-free diet adherence 1
Ongoing gastrointestinal blood loss exceeding oral replacement capacity 1
Severe anemia requiring rapid correction (e.g., pre-operative patients) 2
Preferred IV Formulations:
Ferric carboxymaltose (500-1000 mg single doses, delivered within 15 minutes) is preferred due to convenience and safety profile. 1, 2
Avoid iron dextran preparations due to higher risk of anaphylaxis (0.6-0.7% serious reactions). 4, 1
Resuscitation facilities must be available when administering any intravenous iron. 4
Monitor phosphate levels as IV iron, especially ferric carboxymaltose, can cause hypophosphatemia. 2
Monitoring Strategy
Follow this specific monitoring schedule after correction of anemia: 4, 1
- Every 3 months for the first year
- Once more after another year
- Subsequently only if symptoms of anemia develop
Provide additional iron supplementation if hemoglobin or red cell indices fall below normal. 4, 1
Critical Pitfalls to Avoid
Never use multiple daily doses of oral iron—this increases side effects without improving efficacy. 1
Never stop iron therapy when hemoglobin normalizes—continue for 3 months to replenish stores. 4, 1
Never continue oral iron indefinitely without response—reassess after 4 weeks and switch to IV iron if hemoglobin fails to rise. 1
Never overlook vitamin C supplementation when oral iron response is suboptimal. 1
Never fail to identify and treat the underlying cause while supplementing iron. 4, 1
Never use parenteral iron as first-line unless specific contraindications to oral therapy exist. 1
Special Population Considerations
Inflammatory Bowel Disease:
- Treat active inflammation first to enhance iron absorption and reduce iron depletion. 1
- IV iron is first-line if hemoglobin <10 g/dL with clinically active disease. 1
Celiac Disease:
- Ensure strict adherence to gluten-free diet to improve iron absorption. 1
- Progress to IV iron if oral supplementation fails despite dietary compliance. 1
Post-Bariatric Surgery:
- IV iron is preferred due to disrupted duodenal absorption mechanisms. 1
Failure to Respond
If anemia does not resolve within 6 months despite appropriate iron therapy: 1
- Reassess for ongoing blood loss
- Evaluate for malabsorption syndromes
- Consider further gastrointestinal investigation
- Verify patient adherence to therapy
- Consider hematology consultation for complex cases