What is the first line treatment for iron deficiency anemia?

First-Line Treatment for Iron Deficiency Anemia

Oral iron supplementation should be considered as first-line treatment for iron deficiency anemia in patients with mild anemia, whose disease is clinically inactive, and who have not been previously intolerant to oral iron. 1

Diagnostic Criteria for Iron Deficiency Anemia

Before initiating treatment, it's important to establish the diagnosis of iron deficiency anemia using the following parameters:

• Without inflammation:

  • Serum ferritin <30 μg/L
  • Low transferrin saturation (<20%)
  • Low serum iron
  • Elevated TIBC (total iron binding capacity)
  • Low MCV (microcytic)
  • Elevated RDW

• With inflammation/chronic disease:

  • Serum ferritin up to 100 μg/L may still be consistent with iron deficiency
  • Transferrin saturation <20%
  • Low serum iron
  • Normal to low TIBC
  • Usually normal MCV

Treatment Algorithm

First-Line Treatment: Oral Iron

• Standard dosing: 60-120 mg elemental iron daily 2
• Recommended formulation: Ferrous sulfate 200 mg once daily in the morning with vitamin C to enhance absorption 2
• Alternative dosing strategy: For patients with gastrointestinal side effects, consider alternate-day dosing which may improve absorption and reduce side effects 3
• Expected response: Hemoglobin increase of approximately 1-2 g/dL after 3-4 weeks of treatment 2

When to Switch to Intravenous Iron (First-Line in Special Circumstances)

IV iron should be considered as first-line treatment in the following situations:

1. Clinically active inflammatory disease (e.g., active IBD)
2. Previous intolerance to oral iron
3. Severe anemia (hemoglobin <10 g/dL)
4. Patients who need erythropoiesis-stimulating agents
5. Conditions with impaired oral iron absorption (e.g., celiac disease, post-bariatric surgery)
6. Ongoing blood loss
7. During second and third trimesters of pregnancy when rapid repletion is needed 1, 2, 4

IV Iron Administration

• Recommended formulation: Ferric carboxymaltose (Injectafer)
• Dosing for patients ≥50 kg: 750 mg IV × 2 doses separated by at least 7 days (total 1,500 mg) 5
• Dosing for patients <50 kg: 15 mg/kg body weight IV in two doses separated by at least 7 days 5

Monitoring and Follow-up

• Check hemoglobin after 3-4 weeks of treatment
• A hemoglobin increase of at least 1.0 g/dL at day 14 predicts adequate response to oral iron 6
• If hemoglobin increase is <1.0 g/dL at day 14, consider switching to IV iron 6
• Target values: ferritin ≥100 μg/L and hemoglobin 12-13 g/dL (gender-specific) 2
• Do not check iron studies within 4 weeks of IV iron administration (falsely elevated results) 2

Common Pitfalls to Avoid

1. Inadequate dosing: Ensure appropriate dosing based on severity of anemia
2. Premature discontinuation: Continue treatment until both hemoglobin normalization and iron store repletion
3. Overlooking the underlying cause: Always investigate and treat the cause of iron deficiency
4. Inappropriate parenteral iron use: Reserve for specific indications as outlined above
5. Ignoring inflammation: Interpret ferritin values in context of inflammatory status
6. Poor patient education: Explain importance of compliance and potential side effects

Side Effects and Management

Oral Iron

• Gastrointestinal side effects (constipation, nausea, abdominal pain)
• Management: Take with food, reduce dose, or switch to alternate-day dosing

IV Iron

• Hypersensitivity reactions (rare with modern formulations)
• Infusion reactions
• Hypophosphatemia (particularly with certain formulations)
• Monitor for extravasation during administration

By following this treatment algorithm, iron deficiency anemia can be effectively managed, improving patient morbidity, mortality, and quality of life.