What are the guidelines for iron supplementation in patients with iron deficiency anemia?

Guidelines for Iron Supplementation in Iron Deficiency Anemia

Oral iron supplementation is the first-line treatment for iron deficiency anemia, with ferrous sulfate 200 mg three times daily being the most effective and economical option to correct anemia and replenish iron stores. 1

Oral Iron Therapy

First-line Approach

• Ferrous sulfate 200 mg three times daily is the most cost-effective option, though ferrous gluconate and ferrous fumarate are equally effective 1
• Newer guidelines suggest once-daily dosing or alternate-day dosing may be better tolerated with similar efficacy 1, 2
• Add vitamin C (ascorbic acid) to enhance iron absorption, particularly when response to therapy is poor 1
• Liquid preparations should be considered when tablets are not tolerated 1

Expected Response

• Hemoglobin should rise by approximately 2 g/dL after 3-4 weeks of therapy 1
• A hemoglobin increase <1.0 g/dL at day 14 may identify patients who should be transitioned to IV iron 3
• Continue oral iron for three months after correction of anemia to replenish iron stores 1

Follow-up Monitoring

• Monitor hemoglobin and red cell indices every three months for one year, then after a further year 1
• Additional oral iron should be given if hemoglobin or MCV falls below normal 1
• Consider ferritin estimation in doubtful cases 1
• Further investigation is only necessary if hemoglobin and MCV cannot be maintained with supplementation 1

Intravenous Iron Therapy

Indications for IV Iron

• Intolerance to at least two oral iron preparations 1
• Non-compliance with oral therapy 1
• Ferritin levels that do not improve with a trial of oral iron 1
• Conditions where oral iron is unlikely to be absorbed 1
• Clinically active inflammatory bowel disease 1
• Previous intolerance to oral iron 1
• Hemoglobin below 100 g/L 1
• Patients who need erythropoiesis-stimulating agents 1
• Post-bariatric surgery patients 1

IV Iron Administration

• IV formulations that can replace iron deficits with 1-2 infusions are preferred 1
• For patients ≥50 kg: Ferric carboxymaltose 750 mg IV in two doses separated by at least 7 days (total 1,500 mg) 4
• For patients <50 kg: 15 mg/kg body weight IV in two doses separated by at least 7 days 4
• Monitor for extravasation during administration 4

Special Populations

Inflammatory Bowel Disease

• Determine whether iron deficiency anemia is due to inadequate intake/absorption or gastrointestinal bleeding 1
• Treat active inflammation effectively to enhance iron absorption or reduce iron depletion 1
• Consider IV iron as first-line treatment in patients with clinically active IBD 1

Pre-menopausal Women

• Iron deficiency anemia occurs in 5-10% of menstruating women 1
• Common causes include menorrhagia, pregnancy, and breastfeeding 1
• Pictorial blood loss assessment charts can help quantify menstrual loss with 80% sensitivity/specificity 1

Common Pitfalls and Caveats

• Poor response to oral therapy may be due to:

  • Poor compliance 1
  • Misdiagnosis 1
  • Continued blood loss 1
  • Malabsorption 1

• Parenteral iron considerations:

  • True anaphylaxis is rare, but infusion reactions can occur 1
  • IV iron is not faster than oral iron in raising hemoglobin levels in most cases 1
  • Check serum phosphate levels in patients requiring repeat courses of IV iron 4

• Treatment targets:

  • Resolution of anemia should be achieved by six months in 80% of patients 1
  • 90% of those not responding to treatment should be considered for further investigation 1