What is the treatment for mild iron deficiency anemia?

Treatment for Mild Iron Deficiency Anemia

Oral iron supplementation is the first-line treatment for mild iron deficiency anemia in patients without active inflammation or gastrointestinal disease, using 100-200 mg of elemental iron daily for 3-6 months to normalize hemoglobin and replenish iron stores. 1

Initial Treatment Approach

Oral Iron Therapy

• Start with oral iron at 100-200 mg elemental iron daily (e.g., ferrous sulfate 324 mg tablets contain 65 mg elemental iron, so 2-3 tablets daily) 2, 3, 4
• Continue treatment for 3-6 months to fully replenish iron stores, not just correct hemoglobin 3
• If gastrointestinal side effects occur, reduce to lower doses (even 30-60 mg daily can be effective with longer duration) 1, 5

Treatment Goals

• Normalize hemoglobin levels (>120 g/L for women, >130 g/L for men) 1
• Replenish iron stores (ferritin >100 mg/L) 1
• Improve quality of life and reduce morbidity 1

When to Consider Intravenous Iron

Switch to IV iron if any of the following apply:

• Hemoglobin below 100 g/L (10 g/dL) 1
• Active inflammatory disease (e.g., inflammatory bowel disease with clinical activity) 1
• Previous intolerance to oral iron (gastrointestinal side effects) 1
• Lack of response after 4 weeks of oral therapy (hemoglobin fails to increase by 1 g/dL) 1, 3
• Malabsorption conditions (celiac disease, atrophic gastritis, post-bariatric surgery) 1, 3

IV Iron Dosing

Based on hemoglobin and body weight 1:

• Hemoglobin 100-120 g/L (women) or 100-130 g/L (men): 1000 mg if <70 kg, 1500 mg if ≥70 kg
• Hemoglobin 70-100 g/L: 1500 mg if <70 kg, 2000 mg if ≥70 kg

Monitoring Response

Initial Assessment (4 weeks)

• Recheck hemoglobin after 4 weeks of oral iron therapy 1, 3
• Expect hemoglobin increase of at least 1 g/dL or hematocrit increase of 3% if treatment is effective 1
• If no response despite compliance and absence of acute illness, perform additional testing (MCV, RDW, serum ferritin, transferrin saturation) 1, 3

Long-term Monitoring

• Continue iron supplementation until hemoglobin normalizes AND iron stores are replenished 1
• After successful treatment, monitor ferritin every 6-12 months in patients with mild disease or remission 1
• Reinitiate treatment if ferritin drops below 100 mg/L or hemoglobin falls below normal 1

Important Clinical Considerations

Diagnostic Ferritin Thresholds

• Without inflammation: Ferritin <30 mg/L confirms iron deficiency 1
• With inflammation: Ferritin up to 100 mg/L may still indicate iron deficiency 1
• Ferritin 30-100 mg/L with inflammation suggests mixed iron deficiency and anemia of chronic disease 1

Common Pitfalls

• Don't stop oral iron when hemoglobin normalizes—continue for 2-3 additional months to replenish stores 1
• Don't assume oral iron failure without confirming compliance and ruling out ongoing blood loss 1, 3
• In women of African, Mediterranean, or Southeast Asian ancestry with anemia unresponsive to iron, consider thalassemia minor or sickle cell trait 1
• High-fiber diets can impair iron absorption 6

Special Populations

• Pregnant women: Start with 30 mg/day at first prenatal visit for prevention; use 60-120 mg/day for treatment of anemia 1
• Children: Screen at 1 year of age; treat with age-appropriate iron dosing 1, 4
• IBD patients with inactive disease: Oral iron is appropriate first-line 1