What is the recommended treatment for correcting iron deficiency anemia using iron supplements?

Treatment of Iron Deficiency Anemia with Oral Iron Supplementation

For most patients with iron deficiency anemia, oral ferrous sulfate 100-200 mg elemental iron once daily (or every other day if side effects occur) is the recommended first-line treatment, continued for 3 months after hemoglobin normalization to replenish iron stores. 1

Oral Iron Dosing Strategy

Standard Dosing

• Ferrous sulfate 200 mg three times daily is the traditional regimen, though this is based on limited evidence and may not be optimal 1
• More recent evidence supports 100-200 mg elemental iron once daily as equally effective with better tolerability 2, 3
• For pregnant women: 60-120 mg/day elemental iron 1
• For adolescent girls and women: 60-120 mg/day 1

Alternate-Day Dosing

• Every-other-day dosing may improve absorption and tolerability compared to daily dosing 1
• High iron doses (≥60 mg) stimulate hepcidin elevation that persists 24 hours, reducing absorption of subsequent doses 3
• Give doses in the morning rather than afternoon/evening to optimize absorption based on circadian hepcidin patterns 3

Formulation Selection

• No single oral iron formulation has advantages over others; ferrous sulfate is preferred as the least expensive option 1
• Ferrous gluconate and ferrous fumarate are equally effective alternatives 1
• Liquid preparations may be better tolerated when tablets are not 1

Enhancing Absorption

Add vitamin C (ascorbic acid) to oral iron supplementation to improve absorption, particularly when response is poor 1, 3

Duration of Treatment

Continue iron supplementation for 2-3 months after hemoglobin normalization to replenish iron stores 1

Monitoring Response

• Hemoglobin should increase by 2 g/dL after 3-4 weeks of treatment 1
• If no response after 4 weeks despite compliance and absence of acute illness, further evaluation is needed with additional testing (MCV, RDW, serum ferritin) 1
• Failure to respond suggests: poor compliance, misdiagnosis, continued blood loss, or malabsorption 1

Follow-Up Schedule

• Monitor hemoglobin and red cell indices every 3 months for one year, then annually 1
• Resume iron supplementation if hemoglobin or MCV falls below normal 1

When to Use Intravenous Iron Instead

Intravenous iron should be used if: 1

• Patient does not tolerate oral iron (intolerance to at least two oral preparations) 1
• Ferritin levels do not improve with trial of oral iron
• Hemoglobin <10 g/dL 1
• Active inflammatory bowel disease with compromised absorption 1
• Malabsorption conditions (celiac disease, post-bariatric surgery) 1
• Patient requires erythropoiesis-stimulating agents 1

For IV iron, prefer formulations requiring 1-2 infusions over those requiring multiple doses 1

Special Populations

Pregnant Women

• Start 30 mg/day at first prenatal visit for prevention 1
• Increase to 60-120 mg/day for treatment of anemia 1
• Reduce to 30 mg/day once hemoglobin normalizes for gestational stage 1

Inflammatory Bowel Disease

• IV iron is first-line for active IBD with compromised absorption 1
• Treat underlying inflammation to enhance iron absorption 1

Premenopausal Women <40 Years

• Menstrual loss is the most common cause 1
• Extensive GI investigation may not be required unless other red flags present 1

Common Pitfalls to Avoid

• Do not give multiple daily doses - this reduces fractional absorption due to hepcidin elevation 3
• Do not stop treatment when hemoglobin normalizes - continue 2-3 months longer to replenish stores 1
• Do not use parenteral iron as first-line unless specific indications exist - it is painful, expensive, and carries anaphylaxis risk without faster hemoglobin response 1
• Do not assume non-response means oral iron failure - assess compliance, continued blood loss, and consider malabsorption before switching to IV 1