What is the recommended treatment for a patient with iron deficiency anemia?

Treatment of Iron Deficiency Anemia

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

First-Line Oral Iron Therapy

• Ferrous sulfate 200 mg once daily is the gold standard - it contains 65 mg of elemental iron compared to ferrous gluconate's 38 mg per tablet, making it more cost-effective with no evidence of superior efficacy or tolerability for alternative formulations 1, 2

• Once-daily dosing is superior to multiple daily doses because hepcidin (the iron regulatory hormone) remains elevated for 48 hours after iron intake, blocking further absorption and increasing gastrointestinal side effects without improving efficacy 1

• Add vitamin C (ascorbic acid) 500 mg with each iron dose to enhance absorption, particularly critical in patients with severely low transferrin saturation 1

• Take on an empty stomach for optimal absorption, but taking with food is acceptable if gastrointestinal side effects occur 1

• If daily dosing is not tolerated, switch to every-other-day dosing, which increases fractional iron absorption and improves tolerance with similar efficacy 1

Alternative Oral Formulations (If Ferrous Sulfate Not Tolerated)

• Ferrous fumarate (106 mg elemental iron per 325 mg tablet) or ferrous gluconate (38 mg elemental iron per 324 mg tablet) are equally effective alternatives, though typically more expensive 1, 3

• There is no clinical trial evidence that ferrous gluconate is better tolerated than ferrous sulfate, despite common clinical perception 1

Expected Response and Monitoring

• Hemoglobin should rise by approximately 2 g/dL after 3-4 weeks of treatment - check hemoglobin at 4 weeks to assess response 1

• Failure to achieve this rise indicates poor compliance, continued blood loss, or malabsorption requiring further investigation 1

• Continue oral iron for 3 months after hemoglobin normalizes to fully replenish iron stores - this is a critical step that is frequently missed 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

Switch to IV iron if any of the following conditions are met: 1

• Intolerance to at least two different oral iron preparations despite trying once-daily or alternate-day dosing 1

• Failure of ferritin levels to improve after 4 weeks of compliant oral therapy 1

• Inflammatory bowel disease with active inflammation and hemoglobin <10 g/dL - IV iron is first-line treatment in this scenario 1

• Post-bariatric surgery patients due to disrupted duodenal absorption mechanisms 1

• Celiac disease with inadequate response to oral iron despite strict gluten-free diet adherence 1

• Ongoing gastrointestinal blood loss exceeding oral replacement capacity 1

• Pregnancy during second and third trimesters if oral iron fails (though start with oral iron 60-120 mg/day initially) 1, 4

• Chronic kidney disease or heart failure with iron deficiency 4

Preferred IV Iron Formulations

• Choose IV iron preparations that replace iron deficits in 1-2 infusions rather than multiple infusions to minimize anaphylaxis risk and improve convenience 1

• Ferric carboxymaltose (500-1000 mg single doses, delivered within 15 minutes) is a preferred formulation 1

• Iron dextran can be given as total dose infusion but requires resuscitation facilities available due to higher (though still rare at 0.6-0.7%) risk of anaphylaxis 1

• Avoid iron dextran preparations when safer alternatives are available 1

Special Population Considerations

Pregnant Women

• Start oral low-dose iron 30 mg/day at first prenatal visit for prevention 1
• Treat anemia with 60-120 mg/day elemental iron 1
• Refer for further evaluation if hemoglobin <9.0 g/dL 1
• Use IV iron during second and third trimesters if oral iron fails 1, 4

Inflammatory Bowel Disease

• Treat active inflammation first to enhance iron absorption and reduce iron depletion 1
• Use IV iron as first-line when hemoglobin <10 g/dL with active inflammation 1

Post-Bariatric Surgery

• IV iron is preferred due to anatomic disruption of duodenal absorption 1

Celiac Disease

• Ensure strict adherence to gluten-free diet to improve iron absorption 1
• Screen with antiendomysial antibody and IgA measurement 1
• Progress to IV iron if oral supplementation fails despite dietary compliance 1

Critical Pitfalls to Avoid

• Never prescribe multiple daily doses - this increases side effects without improving efficacy due to hepcidin-mediated absorption blockade 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 1

• Do not delay treatment while awaiting diagnostic workup unless colonoscopy is scheduled within days 1

Failure to Respond

If anemia does not resolve within 6 months despite appropriate iron therapy: 1

• Reassess for ongoing blood loss (gastrointestinal evaluation with upper endoscopy and colonoscopy in men and postmenopausal women; assess menstrual blood loss in premenopausal women) 1

• Evaluate for malabsorption syndromes (celiac disease screening, consider post-bariatric surgery anatomy) 1

• Verify patient adherence to therapy 1

• Consider hematology consultation for complex cases 1