What is the recommended oral iron formulation for patients with iron deficiency?

Recommended Oral Iron Formulation for Iron Deficiency

Ferrous sulfate is the preferred oral iron formulation for patients with iron deficiency due to its cost-effectiveness, with no single formulation having proven advantages over others in terms of efficacy. 1, 2

First-Line Treatment Options

• Ferrous sulfate (200mg tablet containing 65mg elemental iron) is the most cost-effective iron formulation and should be used as first-line therapy 1, 2, 3
• Alternative ferrous salts can be considered if ferrous sulfate is not tolerated:
  • Ferrous fumarate (provides similar elemental iron content) 1, 2
  • Ferrous gluconate (provides lower elemental iron content) 1, 2
• All standard ferrous preparations have similar efficacy when equivalent elemental iron doses are administered 1, 2

Optimal Dosing Strategy

• Once-daily dosing of 50-100mg elemental iron (e.g., one ferrous sulfate 200mg tablet daily) is recommended rather than multiple daily doses 1, 2
• Taking iron on an empty stomach maximizes absorption, though this may increase gastrointestinal side effects 2
• Alternate-day dosing may be better tolerated with similar or equal rates of iron absorption compared to daily dosing 1, 2
• The absence of a hemoglobin rise of at least 10 g/L after 2 weeks of daily oral iron therapy strongly predicts subsequent treatment failure (sensitivity 90.1%, specificity 79.3%) 1

Strategies to Improve Absorption and Tolerability

• Add vitamin C (ascorbic acid) to oral iron supplementation to enhance absorption 1, 2
• Avoid taking iron with tea, coffee, or calcium-containing foods, which inhibit absorption 2
• If standard doses are not tolerated, consider:
  • Reduced dose
  • Taking with food (though this reduces absorption)
  • Switching to alternate-day dosing
  • Trying a different iron salt 1, 2

Duration of Treatment

• Continue iron supplementation for three months after correction of anemia to replenish iron stores 1, 2
• Monitor hemoglobin levels at regular intervals (suggested every 4 weeks until normalized) 1, 2

When to Consider Alternative Approaches

• Intravenous iron should be used when:
  • Patient does not tolerate oral iron despite modifications
  • Ferritin levels do not improve with oral iron trial
  • Patient has conditions where oral iron absorption is impaired (e.g., inflammatory bowel disease, post-bariatric surgery) 1, 2, 4
• Modified-release preparations are generally not recommended as they are indicated as "less suitable for prescribing" according to guidelines 1, 2
• Avoid multivitamin preparations as the sole source of iron supplementation as they typically contain insufficient elemental iron for treating iron deficiency anemia 2

Common Pitfalls to Avoid

• Prescribing multiple daily doses of iron, which increases side effects without improving absorption 1, 2
• Failing to continue treatment long enough to replenish iron stores after hemoglobin normalizes 1, 2
• Not monitoring the hemoglobin response within the first 2-4 weeks to identify non-responders early 1, 2
• Overlooking the need to investigate the underlying cause of iron deficiency while treating with iron supplementation 1, 4

Following these evidence-based recommendations will ensure optimal management of iron deficiency with oral iron supplementation, maximizing efficacy while minimizing side effects.