What is the first-line treatment for iron deficiency anemia?

First-Line Treatment for Iron Deficiency Anemia

The preferred first-line treatment for iron deficiency anemia is oral iron therapy, specifically ferrous sulfate 200 mg once daily (providing approximately 65 mg of elemental iron), as it is effective, inexpensive, and safe for most patients. 1

Diagnosis of Iron Deficiency Anemia

Before initiating treatment, confirm the diagnosis with:

• Serum ferritin <30 μg/L in patients without inflammation
• Serum ferritin <100 μg/L in patients with inflammation
• Transferrin saturation <20%
• Complete blood count showing low hemoglobin 1

Oral Iron Therapy Protocol

• Formulation: Ferrous sulfate is the preferred oral iron formulation
• Dosage: 200 mg once daily (providing approximately 65 mg of elemental iron)
• Administration: Take with vitamin C to enhance absorption
• Duration: Continue for 3-6 months to replenish iron stores 1

Monitoring Response

• Check hemoglobin response after 3-4 weeks of therapy (should rise by approximately 2 g/dL)
• Monitor hemoglobin and red cell indices at 3-month intervals for one year
• Complete follow-up iron studies after 8-10 weeks of treatment
• Continue treatment for 3-6 months after normalization of hemoglobin to replenish iron stores 1

When to Consider Intravenous Iron

IV iron should be considered first-line in specific situations:

1. Patients with clinically active inflammatory bowel disease
2. Previous intolerance to oral iron
3. Hemoglobin below 10 g/dL
4. Patients who need erythropoiesis-stimulating agents 2
5. Patients with impaired iron absorption (post-bariatric surgery, celiac disease)
6. Chronic kidney disease
7. When oral iron is ineffective or contraindicated 1, 3

IV Iron Administration

For patients requiring IV iron:

• Dosing based on hemoglobin and body weight:

  • Hemoglobin 10-12 g/L (women) or 10-13 g/L (men):
    • <70 kg: 1000 mg
    • ≥70 kg: 1500 mg
  • Hemoglobin 7-10 g/L:
    • <70 kg: 1500 mg
    • ≥70 kg: 2000 mg 1

• Ferric carboxymaltose (Injectafer) is administered:

  • For patients ≥50 kg: 750 mg IV in two doses separated by at least 7 days (total 1,500 mg)
  • For patients <50 kg: 15 mg/kg body weight IV in two doses separated by at least 7 days 3

Common Pitfalls to Avoid

1. Underdosing oral iron: Using inadequate doses that fail to replenish iron stores
2. Checking ferritin too early after IV iron administration (will be falsely elevated)
3. Failing to identify and treat the underlying cause of iron deficiency
4. Not monitoring for side effects of oral iron (constipation, nausea, abdominal pain)
5. Missing patients who need IV iron instead of oral therapy

Special Considerations

• Inflammatory conditions: Patients with inflammatory conditions (IBD, CKD, heart failure) often respond better to IV iron than oral iron 2, 1
• Pregnancy: Iron requirements increase during pregnancy; consider IV iron in second and third trimesters if oral iron is ineffective 4
• Chronic kidney disease: IV iron is preferred for patients with severe anemia (Hb < 10 g/dL) and advanced CKD (GFR < 25 mL/min) 1

By following these evidence-based guidelines, iron deficiency anemia can be effectively treated while minimizing side effects and optimizing patient outcomes.