What is the first line treatment for iron deficiency anemia?

First-Line Treatment for Iron Deficiency Anemia

The first-line treatment for iron deficiency anemia is oral iron supplementation, most commonly with ferrous sulfate 200 mg three times daily, although ferrous gluconate and ferrous fumarate are equally effective alternatives. 1

Oral Iron Therapy

Recommended Formulations and Dosing

• Ferrous sulfate 200 mg three times daily is the most simple, effective, and economical option 1
• Alternative formulations include ferrous gluconate and ferrous fumarate, which may be better tolerated by some patients 1
• Liquid preparations can be considered for patients who cannot tolerate tablets 1
• Lower doses may be as effective and better tolerated in patients experiencing side effects 1
• Recent evidence suggests that once-daily or alternate-day dosing may be as effective as multiple daily doses while reducing side effects 1

Enhancing Absorption

• Adding ascorbic acid (vitamin C) 500 mg with iron supplements enhances absorption 1
• Taking iron with meat protein can improve absorption 1
• Iron is better absorbed when taken on an empty stomach, though some patients may tolerate it better with meals 1

Duration of Therapy

• Oral iron should be continued for 3 months after correction of anemia to replenish iron stores 1
• Hemoglobin should rise by approximately 2 g/dL after 3-4 weeks of therapy 1
• A hemoglobin increase of at least 1 g/dL at day 14 of therapy is a good predictor of successful response to oral iron 2

When to Consider Intravenous Iron

Intravenous iron should be considered as first-line treatment in specific situations:

• Patients with clinically active inflammatory bowel disease 1
• Previous intolerance to at least two oral iron preparations 1
• Poor compliance with oral therapy 1
• Hemoglobin below 10 g/dL 1
• Patients requiring erythropoiesis-stimulating agents 1
• Conditions with impaired iron absorption (celiac disease, post-bariatric surgery) 1, 3
• Ongoing blood loss exceeding intestinal absorption capacity 4

Monitoring Response to Therapy

• Hemoglobin should increase by approximately 2 g/dL after 3-4 weeks of oral iron therapy 1
• Failure to respond is typically due to poor compliance, misdiagnosis, continued blood loss, or malabsorption 1
• If hemoglobin increases by less than 1 g/dL after 14 days of oral therapy, consider switching to intravenous iron 2
• After successful treatment, monitor for recurrence with periodic checks of hemoglobin and iron stores 1

Common Pitfalls and Caveats

• Gastrointestinal side effects (constipation, diarrhea, nausea) are common with oral iron and may reduce compliance 1, 5
• Parenteral iron carries a risk of anaphylactic reactions, though newer formulations have improved safety profiles 1
• Failure to investigate and treat the underlying cause of iron deficiency can lead to recurrence 1
• In inflammatory conditions, serum ferritin may be falsely elevated due to its role as an acute phase reactant 1
• Oral iron supplementation may be ineffective in patients with ongoing blood loss or inflammatory conditions 4, 3

Special Populations

• In patients with inflammatory bowel disease, intravenous iron is more effective and better tolerated than oral iron 1
• For pregnant women in their second and third trimesters with iron deficiency anemia, intravenous iron may be more appropriate 3
• In chronic kidney disease, heart failure, and cancer patients with iron deficiency, intravenous iron is often preferred 3