What is the recommended treatment for iron replacement in patients with iron deficiency anemia?

Iron Replacement for Iron Deficiency Anemia

For patients with iron deficiency anemia, oral iron supplementation with ferrous sulfate 200 mg (65 mg elemental iron) once daily in the morning is the recommended first-line treatment, with intravenous iron reserved for those who fail to respond, cannot tolerate oral therapy, or have conditions with impaired absorption. 1

Oral Iron Therapy

First-Line Approach

• Preferred formulation: Ferrous sulfate 200 mg (65 mg elemental iron) once daily 1
  • Most cost-effective option (approximately £1.00 for 28 days of treatment) 1
  • Take in the fasting state to maximize absorption 1
  • Morning dosing is preferred due to circadian hepcidin patterns 2

Dosing Considerations

• Dosage: 50-100 mg of elemental iron daily is sufficient 1
• Frequency: Once-daily dosing is recommended; alternate-day dosing may be considered for patients with GI side effects 1, 2
• Duration: Continue for 3 months after correction of anemia to replenish iron stores 1
• Adjunct: Add vitamin C (ascorbic acid) to improve iron absorption 1, 3

Monitoring Response

• Check hemoglobin after 2 weeks of treatment
  • A rise of at least 10 g/L indicates adequate response 1
  • Absence of this response strongly predicts treatment failure (sensitivity 90.1%, specificity 79.3%) 1
• Monitor hemoglobin every 4 weeks until normalized 1
• After normalization, check hemoglobin quarterly for 1 year, then after another year 1

Intravenous Iron Therapy

Indications

• Intolerance to oral iron (significant GI side effects) 1
• Failure to respond to oral iron therapy 1
• Conditions with impaired absorption:
  • Inflammatory bowel disease with active inflammation 1, 3
  • Post-bariatric surgery 1, 4
  • Celiac disease not responding to gluten-free diet and oral iron 1
• Chronic inflammatory conditions 4
• Ongoing blood loss 1
• Need for rapid iron repletion 5

Preferred IV Formulations

• Ferric carboxymaltose or ferric derisomaltose are preferred as they:
  • Require fewer infusions (1-2 doses can replace total iron deficit) 1
  • Have shorter infusion times (15-30 minutes) 1
  • Don't require test doses 1
  • FDA-approved for IDA in patients with oral iron intolerance or unsatisfactory response 5

Dosing for IV Iron

• For patients ≥50 kg: 750 mg IV in two doses separated by at least 7 days (total 1,500 mg) 5
• For patients <50 kg: 15 mg/kg IV in two doses separated by at least 7 days 5
• Alternative for adults ≥50 kg: single dose of 15 mg/kg up to 1,000 mg 5

Special Populations and Considerations

Portal Hypertensive Gastropathy

• Start with oral iron supplements
• Switch to IV iron if there's ongoing bleeding and poor response to oral therapy 1

Inflammatory Bowel Disease

• IV iron is preferred when active inflammation is present 1, 3
• Treat underlying inflammation to enhance iron absorption 1

Pregnancy

• Iron deficiency affects up to 84% of women in the third trimester 4
• IV iron may be indicated during second and third trimesters if oral iron is ineffective 4

Heart Failure

• IV iron (ferric carboxymaltose) is indicated for iron deficiency in adults with heart failure to improve exercise capacity 5

Common Pitfalls to Avoid

1. Overuse of blood transfusions: Transfusion should be reserved for severe symptomatic anemia or circulatory compromise (target Hb 70-90 g/L) 1

2. Switching between different iron salts: This practice is not supported by evidence when side effects occur; consider alternate-day dosing, ferric maltol, or IV iron instead 1

3. Using modified-release preparations: These are less suitable for prescribing and more expensive 1

4. Inadequate monitoring: Failure to check response at 2 weeks may delay identification of non-responders 1

5. Insufficient treatment duration: Stopping oral iron once hemoglobin normalizes without continuing for 3 months to replenish stores 1

6. Ignoring hypophosphatemia risk: Monitor serum phosphate levels in patients receiving repeated IV iron courses 5

By following these evidence-based recommendations, most patients with iron deficiency anemia will achieve successful correction of anemia and replenishment of iron stores, improving morbidity, mortality, and quality of life outcomes.