What is the recommended oral iron replacement regimen for patients with iron deficiency anemia?

Recommended Oral Iron Replacement Regimen for Iron Deficiency Anemia

The recommended oral iron replacement regimen for iron deficiency anemia is ferrous sulfate 50-100 mg of elemental iron once daily, preferably taken in the morning on an empty stomach with vitamin C to enhance absorption. 1, 2

First-Line Oral Iron Therapy

Preferred Iron Formulation

• Ferrous sulfate is the preferred first-line oral iron supplement due to its effectiveness, bioavailability, and cost-effectiveness 1, 2
• Each 324 mg tablet of ferrous sulfate contains 65 mg of elemental iron 3
• No single formulation of oral iron has proven advantages over others, but ferrous sulfate is least expensive 1

Dosing Strategy

• Dosage: 50-100 mg of elemental iron once daily 1, 2
• Timing: Take in the morning on an empty stomach 2
• Frequency: Daily or alternate-day dosing 1, 2, 4
  • Alternate-day dosing may improve absorption and reduce side effects as hepcidin levels rise after iron intake, blocking further absorption for up to 48 hours 2, 4
• Duration: Continue for 3 months after hemoglobin normalizes to ensure adequate repletion of marrow iron stores 1, 2

Absorption Enhancement

• Take with 500 mg vitamin C (ascorbic acid) to enhance absorption 1, 2
• Avoid taking with:
  • Tea or coffee (wait at least 1 hour after iron intake)
  • Calcium supplements
  • High-fiber foods 2

Monitoring Response

• Check hemoglobin and red cell indices every 4 weeks until normalization 2
• Monitor for recurrent iron deficiency every 3-6 months for at least a year after correction 1, 2
• Target ferritin >100 μg/L to ensure replenishment of iron stores 2

Alternative Oral Iron Options

• Ferrous gluconate: 324 mg tablet contains 38 mg of elemental iron 5
• Ferrous fumarate: Available in various formulations (69-106 mg elemental iron per tablet) 1
• Ferric maltol: May be considered for patients with previous intolerance to traditional iron salts 1

When to Consider Parenteral Iron

Intravenous iron should be considered when:

• Oral iron is contraindicated
• Oral iron is ineffective (ferritin levels do not improve with trial of oral iron)
• Oral iron is not tolerated (significant gastrointestinal side effects) 1, 2
• Patient has conditions where oral iron absorption is impaired:
  • Active inflammatory bowel disease
  • Post-bariatric surgery
  • Celiac disease with severe villous atrophy 2
• Severe anemia (hemoglobin <10 g/dL) requiring rapid correction 2, 6

Common Pitfalls to Avoid

• Prescribing multiple daily doses, which may not improve absorption due to hepcidin elevation 2, 4
• Using modified-release preparations, which are less effective due to reduced absorption in the small intestine 1
• Delaying intravenous iron therapy when clearly indicated 2
• Overreliance on ferritin alone for diagnosis in inflammatory conditions 2, 6
• Failure to identify and address underlying causes of iron deficiency while treating with iron 6

By following this evidence-based regimen for oral iron replacement, clinicians can effectively manage iron deficiency anemia while minimizing side effects and optimizing patient outcomes.