What is the appropriate treatment for a patient with iron deficiency anemia?

Treatment of Iron Deficiency Anemia

Start oral ferrous sulfate 200 mg once daily, which is the preferred first-line treatment for this patient with severe iron deficiency anemia (ferritin 10, iron saturation 4%). 1, 2

Immediate Treatment Approach

Oral Iron Therapy (First-Line)

• Prescribe ferrous sulfate 200 mg (equivalent to 65 mg elemental iron) once daily rather than multiple daily doses, as once-daily dosing improves tolerability while maintaining effectiveness 1, 2, 3
• Take on an empty stomach for optimal absorption, though taking with food is acceptable if gastrointestinal side effects occur 1
• Add vitamin C (ascorbic acid) 500 mg with the iron dose to enhance absorption, particularly important given the severely low iron saturation of 4% 1, 2
• Alternative formulations (ferrous gluconate or ferrous fumarate) are equally effective if ferrous sulfate is not tolerated 1, 2

Expected Response and Monitoring

• Hemoglobin should rise by approximately 2 g/dL after 3-4 weeks of treatment 1, 2
• If no response occurs within 4 weeks, assess for non-adherence, ongoing blood loss, malabsorption, or misdiagnosis 1, 2
• Continue iron therapy for 3 months after anemia correction to fully replenish iron stores 2
• Monitor hemoglobin and red cell indices every 3 months for the first year, then again after another year 2

When to Switch to Intravenous Iron

Consider IV iron if the patient meets any of these criteria: 1, 2

• Intolerance to at least two different oral iron preparations 1, 2
• Inadequate response to oral iron after 4 weeks of appropriate therapy 1, 2
• Conditions affecting iron absorption (inflammatory bowel disease with active inflammation, celiac disease, post-bariatric surgery) 1, 2
• Ongoing gastrointestinal blood loss exceeding oral replacement capacity 2

IV Iron Formulations

• Prefer formulations that can replace iron deficits with 1-2 infusions rather than those requiring multiple infusions 1, 2
• True anaphylaxis is very rare; most reactions are complement activation-related pseudo-allergy (infusion reactions) and should be treated as such 1

Identify and Treat Underlying Cause

This patient requires investigation for the source of iron deficiency: 1, 2

• Given the microcytic anemia (MCV 71) and severely depleted iron stores (ferritin 10, iron saturation 4%), identify the source of iron loss 4
• For premenopausal women: assess menstrual blood loss (menorrhagia is common) and dietary intake 1, 4
• For men and postmenopausal women: gastrointestinal evaluation with upper endoscopy and colonoscopy is mandatory to exclude malignancy 1, 5
• Consider celiac disease screening with antiendomysial antibody and IgA measurement 1
• Evaluate for use of NSAIDs, inflammatory bowel disease, or other chronic inflammatory conditions 4

Common Pitfalls to Avoid

• Do not prescribe multiple daily doses (e.g., three times daily) as this increases side effects without improving efficacy 2, 6
• Do not stop iron therapy when hemoglobin normalizes - continue for 3 months to replenish stores 2
• Do not continue oral iron indefinitely without response - reassess after 4 weeks and switch to IV iron if hemoglobin fails to rise 2
• Do not overlook vitamin C supplementation when oral iron response is suboptimal, particularly with iron saturation this low 1, 2
• Do not fail to identify and treat the underlying cause while supplementing iron 1, 2
• Do not use parenteral iron as first-line unless specific contraindications to oral therapy exist 1, 5

Failure to Respond

If anemia does not resolve within 6 months despite appropriate iron therapy: 1, 2

• Reassess for ongoing blood loss 2
• Evaluate for malabsorption syndromes (celiac disease, atrophic gastritis, H. pylori infection) 1, 4
• Consider further gastrointestinal investigation 1
• Verify patient adherence to therapy 1, 2
• Consider hematology consultation for complex cases 1