What is the best oral iron supplement for a 31-year-old female with iron deficiency anemia and low ferritin levels?

Best Oral Iron Supplementation for Iron Deficiency Anemia in a 31-Year-Old Female

For a 31-year-old female with iron deficiency anemia and low ferritin, ferrous sulfate 200 mg once daily (providing 65 mg of elemental iron) is the recommended first-line oral iron therapy due to its effectiveness, low cost, and established efficacy. 1

Initial Treatment Approach

• Ferrous sulfate 200 mg once daily (65 mg elemental iron) is the initial treatment of choice for iron deficiency anemia in this patient population 1
• Alternative ferrous salts that can be considered if ferrous sulfate is not tolerated include:
  • Ferrous fumarate (provides 69-106 mg elemental iron per tablet) 1
  • Ferrous gluconate (provides 37-38 mg elemental iron per tablet) 1, 2
• Treatment should be continued for approximately 3 months after hemoglobin normalizes to ensure adequate repletion of marrow iron stores 1

Dosing Considerations

• Once-daily dosing is recommended rather than multiple daily doses, as studies show similar iron absorption with once-daily dosing compared to divided doses 1
• Recent evidence suggests alternate-day dosing may improve fractional iron absorption and reduce side effects, though this approach needs further study before routine implementation 1, 3
• Morning administration is preferred as it may optimize absorption by avoiding the circadian increase in hepcidin that occurs later in the day 3

Optimizing Absorption

• Iron supplements should ideally be taken on an empty stomach to maximize absorption 1
• Taking iron with 80-500 mg of vitamin C (ascorbic acid) can enhance absorption by forming a chelate with iron and preventing formation of insoluble iron compounds 1
• Patients should avoid consuming tea or coffee within one hour of taking iron supplements as these are powerful inhibitors of iron absorption 1

Monitoring Response

• Monitor hemoglobin response within the first 4 weeks of treatment 1
• Expect hemoglobin to increase by approximately 1 g/dL within 2 weeks of supplementation in patients responding to therapy 1
• After restoration of hemoglobin and iron stores, monitor blood counts periodically (approximately every 6 months initially) to detect recurrent iron deficiency anemia 1

Managing Side Effects

• Common side effects include constipation (12%), diarrhea (8%), and nausea (11%) 1
• If standard doses are not tolerated, consider:
  • Reduced dose (one tablet every other day) 1
  • Taking with food (though this may reduce absorption) 1
  • Switching to an alternative iron formulation 1

When to Consider Parenteral Iron

• Parenteral iron should be considered when oral iron is:
  • Contraindicated
  • Ineffective (no increase in hemoglobin after 4 weeks of adherent use)
  • Not tolerated despite dose adjustments or formulation changes 1
• Intravenous iron is also indicated in situations where oral iron absorption is likely impaired (e.g., bariatric surgery, active inflammatory bowel disease) 1

Special Considerations

• Ferric maltol may be considered in patients with previous intolerance to traditional iron salts, though it has a relatively low iron content and is more expensive than traditional ferrous salts 1
• Avoid multivitamin preparations as the sole source of iron supplementation as they typically contain insufficient elemental iron (up to 14 mg) for treating iron deficiency anemia 1
• For this premenopausal woman with iron deficiency anemia, investigation for underlying causes (especially gastrointestinal sources of blood loss) should be considered alongside iron replacement therapy 1, 4