What is the best treatment approach for a patient diagnosed with iron deficiency anemia?

Management of Iron Deficiency Anemia

For patients diagnosed with iron deficiency anemia, oral iron supplementation should be used as first-line treatment, with intravenous iron reserved for specific clinical scenarios including intolerance to oral iron, poor response to oral therapy, active inflammation, or hemoglobin below 10 g/dL. 1

Diagnostic Confirmation

• Iron deficiency anemia is confirmed by:
  • Low hemoglobin levels
  • Low serum ferritin (<30 ng/mL in patients without inflammation)
  • Transferrin saturation <20%
  • Microcytosis and hypochromia
  • Increased red cell distribution width (RDW) 2

Treatment Algorithm

First-Line Therapy: Oral Iron

• Formulation: Ferrous sulfate is preferred as the least expensive iron formulation with no advantages of other formulations 1
• Dosing:
  • 50-100 mg of elemental iron daily (equivalent to 200 mg ferrous sulfate once daily) 1, 3
  • Consider every-other-day dosing if daily dosing causes side effects 1, 4
• Administration:
  • Take with vitamin C (orange juice, vitamin C supplement) to enhance absorption 1, 3
  • Take on an empty stomach if tolerated
  • Avoid taking with tea, coffee, calcium, or antacids which inhibit absorption 3
• Duration: Continue for 3 months after normalization of hemoglobin to replenish iron stores 3
• Monitoring: Check complete blood count and iron studies every 3 months until normalized 3

When to Use Intravenous Iron (First-Line)

Intravenous iron should be considered first-line in patients with:

• Active inflammatory bowel disease 1
• Hemoglobin below 10 g/dL 1
• Previous intolerance to oral iron 1
• Patients requiring erythropoiesis-stimulating agents 1
• Conditions with impaired iron absorption (post-bariatric surgery, celiac disease) 1, 2
• Ongoing blood loss exceeding absorption capacity 5

Intravenous Iron Administration

• Formulation choice: Prefer IV iron formulations that can replace iron deficits with 1-2 infusions 1
• Dosing calculation:
  • For hemoglobin 10-12 g/dL (women) or 10-13 g/dL (men):
    • Body weight <70 kg: 1000 mg
    • Body weight ≥70 kg: 1500 mg
  • For hemoglobin 7-10 g/dL:
    • Body weight <70 kg: 1500 mg
    • Body weight ≥70 kg: 2000 mg 1
• Safety: All IV iron formulations have similar risks; true anaphylaxis is rare 1

Special Considerations

Inflammatory Bowel Disease

• Determine if anemia is due to inadequate intake/absorption or blood loss
• Treat active inflammation to enhance iron absorption 1
• IV iron is recommended for patients with active inflammation 1

Pregnancy

• Higher iron requirements (27 mg daily) 3
• Consider IV iron during second and third trimesters if oral iron ineffective 3, 2

Heavy Menstrual Bleeding

• Requires particular attention to iron intake 3
• Treat underlying cause of bleeding while correcting iron deficiency

Common Pitfalls to Avoid

1. Inadequate treatment duration: Continue iron supplementation for 3 months after normalization of hemoglobin 3
2. Improper administration: Taking oral iron with meals or with absorption inhibitors (tea, coffee, calcium) 3
3. Excessive dosing: Higher doses don't improve absorption and increase side effects 4
4. Failure to add vitamin C: Vitamin C significantly enhances non-heme iron absorption 1, 3
5. Overlooking underlying cause: Always investigate and treat the underlying cause of iron deficiency 2, 6
6. Delaying IV iron when indicated: Don't persist with oral iron when IV iron is clearly indicated 5

By following this evidence-based approach, most patients with iron deficiency anemia can achieve normalization of hemoglobin levels and replenishment of iron stores, leading to improved quality of life and reduced morbidity.