What is the recommended treatment for Iron Deficiency Anemia (IDA)?

Treatment for Iron Deficiency Anemia

Start with oral iron supplementation at 50-100 mg elemental iron once daily taken on an empty stomach (e.g., one ferrous sulfate 200 mg tablet daily), and reserve intravenous iron for patients with intolerance, malabsorption, ongoing blood loss, or inflammatory conditions. 1

Initial Oral Iron Therapy

Dosing Strategy:

• Prescribe 50-100 mg elemental iron once daily in the fasting state as the optimal initial regimen, balancing efficacy with tolerability 1
• Ferrous sulfate 200 mg tablets (containing 65 mg elemental iron) are the simplest and least expensive option 1
• Alternative ferrous salts include ferrous fumarate (69-106 mg elemental iron per tablet) or ferrous gluconate (37 mg elemental iron per tablet), though evidence does not support switching between traditional iron salts for intolerance 1

Alternative Dosing for Intolerance:

• Alternate-day dosing (e.g., 120 mg elemental iron every other day) produces similar hemoglobin increments with significantly lower nausea rates, though slower initial response 1
• Lower daily doses (60 mg twice daily vs 120 mg alternate days) produce faster hemoglobin rise but similar ultimate outcomes 1
• Ferric maltol 30 mg twice daily is better tolerated than traditional salts but more expensive and slower to replenish stores, normalizing hemoglobin in 63-66% at 2 weeks and 89% at 1 year 1

Common Pitfall: Taking iron with food or using enteric-coated formulations improves tolerability but significantly decreases absorption 1

Monitoring Response

Early Assessment (Critical):

• Check hemoglobin at 2 weeks: absence of at least 10 g/L rise predicts subsequent treatment failure with 90.1% sensitivity and 79.3% specificity 1
• If inadequate 2-week response, evaluate for non-compliance, malabsorption, ongoing bleeding, systemic disease, bone marrow pathology, hemolysis, or concurrent B12/folate deficiency 1

Ongoing Monitoring:

• Recheck hemoglobin every 4 weeks until normalized 1
• Typical response shows hemoglobin improvement within 1 month of oral therapy 1

Duration:

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

Intravenous Iron Therapy

Indications for IV Iron:

• Intolerance to oral iron with significant GI disturbance 1
• Inadequate response to oral iron after appropriate trial 1
• Malabsorption syndromes (celiac disease, post-gastric surgery, inflammatory bowel disease) 1
• Chronic kidney disease 1
• Active inflammatory bowel disease with compromised absorption 1
• Ongoing blood loss exceeding oral replacement capacity 1
• Severe symptomatic anemia requiring rapid correction 1

IV Iron Formulations (UK/Europe):

• Ferric carboxymaltose: 1000 mg maximum single dose (or 20 mg/kg, whichever lower), 15-minute infusion, no test dose required, cost £154.23 per 1000 mg 1
• Ferric derisomaltose: 20 mg/kg maximum single dose, 15-30 minute infusion, no test dose required, cost £169.50 per 1000 mg 1
• Iron sucrose: 200 mg per injection, 30-minute infusion, test dose required, cost £102 per 1000 mg 1
• Iron dextran: Total dose replacement possible (20 mg/kg), 4-6 hours infusion, test dose required, cost £79.70 per 1000 mg 1

IV Iron Formulations (US):

• Ferric carboxymaltose (Injectafer): 750 mg IV in two doses separated by ≥7 days (total 1500 mg per course) for patients ≥50 kg; 15 mg/kg for patients <50 kg 2
• Alternative single-dose: 15 mg/kg up to maximum 1000 mg per course 2
• Low molecular weight iron dextran (Infed): requires test dose due to anaphylaxis risk 1
• Iron sucrose, ferric gluconate, ferumoxytol: approved for CKD-associated IDA 1

IV Iron Advantages:

• Produces clinically meaningful hemoglobin response within 1 week 1
• More effective than oral therapy in chronic disease, continuing blood loss, impaired absorption, or GI inflammatory pathology 1

Safety Monitoring:

• Check serum phosphate levels before repeat IV iron courses, especially if repeat treatment needed within 3 months, as hypophosphatemia can cause bone softening and fractures 2
• Monitor for hypersensitivity reactions during and for at least 30 minutes after infusion 2

Blood Transfusion

Transfusion is rarely required and should be reserved for severe symptomatic anemia with circulatory compromise 1

When Transfusion Used:

• Target hemoglobin 70-90 g/L (80-100 g/L with unstable coronary artery disease) 1
• Must follow with iron replacement since each unit contains only ~200 mg elemental iron, insufficient to replenish stores in severe IDA 1
• Parenteral iron should be considered as alternative before transfusion 1

Special Populations

Inflammatory Bowel Disease:

• Parenteral iron more effective than oral therapy with active inflammation 1
• Intolerance and malabsorption of oral iron are particular problems 1

Chronic Heart Failure with Iron Deficiency:

• Parenteral iron improves symptoms, quality of life, and exercise capacity even without anemia 1

Chronic Kidney Disease:

• Functional iron deficiency common; IV iron formulations specifically approved for this indication 1