What is the first line treatment for iron deficiency anemia?

First-Line Treatment for Iron Deficiency Anemia

Oral iron supplementation with ferrous sulfate 200 mg three times daily is the first-line treatment for iron deficiency anemia and should be continued for three months after correction of anemia to replenish iron stores. 1, 2

Diagnosis of Iron Deficiency Anemia

Iron deficiency anemia is diagnosed based on:

• Hemoglobin below normal range (WHO definition)
• Low MCV (<76 fl)
• Low serum ferritin (<30 μg/L without inflammation, <100 μg/L with inflammation)
• Low transferrin saturation (<20%)

Treatment Algorithm

First-Line Treatment: Oral Iron

• Formulation: Ferrous sulfate 200 mg three times daily 1, 2
• Alternative formulations: Ferrous gluconate or ferrous fumarate (equally effective) 1
• Duration: Continue for 3 months after normalization of hemoglobin to replenish iron stores 1, 2
• Adjunct: Consider adding ascorbic acid (vitamin C) to enhance iron absorption 1, 2

When to Use Intravenous Iron (First-Line)

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

• Clinically active inflammatory bowel disease 1
• Previous intolerance to oral iron 1
• Hemoglobin below 100 g/L (10 g/dL) 1, 2
• Patients requiring erythropoiesis-stimulating agents 1
• Severe anemia with advanced chronic kidney disease (GFR <25 mL/min) 2
• Malabsorption conditions (post-bariatric surgery, celiac disease) 2

Monitoring Response

1. Check hemoglobin response after 3-4 weeks of therapy (should rise by approximately 2 g/dL) 2
2. Monitor hemoglobin and red cell indices at 3-month intervals for one year, then after another year 1, 2
3. Complete follow-up iron studies after 8-10 weeks of treatment 2
4. Provide additional iron if hemoglobin or MCV falls below normal 1, 2

Special Considerations

Dosing Optimization

Recent evidence suggests that lower doses (100 mg once daily) may be sufficient for asymptomatic patients with mild anemia, with 200 mg daily reserved for severe anemia or symptomatic patients 3. Lower doses or alternate-day dosing may improve tolerability while maintaining efficacy.

Common Pitfalls to Avoid

1. Inadequate duration of therapy: Treatment must continue for 3 months after hemoglobin normalization to replenish iron stores 1, 2
2. Misinterpreting ferritin levels: In inflammatory conditions, ferritin up to 100 μg/L may still indicate iron deficiency 1, 2
3. Checking ferritin too early: Avoid checking ferritin too soon after IV iron administration as levels will be falsely elevated 2
4. Ignoring gastrointestinal side effects: GI side effects are common with oral iron and may reduce compliance 4; consider alternate-day dosing or different formulations if side effects occur
5. Missing underlying causes: Always investigate the underlying cause of iron deficiency (gastrointestinal bleeding, malabsorption, inadequate intake, etc.) 5

In summary, while oral iron supplementation with ferrous sulfate remains the cornerstone of treatment for iron deficiency anemia, the approach should be adjusted based on severity, underlying conditions, and patient tolerance. Intravenous iron has specific indications and should be considered when oral therapy is inappropriate or ineffective.