What is the best course of treatment for a patient with iron deficiency anemia, characterized by low hemoglobin (Hgb) levels, microcytic anemia (low MCV), and low iron levels?

Management of Iron Deficiency Anemia with Low Hemoglobin, Low MCV, and Low Iron

All patients with iron deficiency anemia should receive iron supplementation to correct anemia and replenish body stores, with oral ferrous sulfate 200 mg three times daily as first-line therapy. 1

Immediate Treatment Approach

Oral Iron Supplementation (First-Line)

• Start ferrous sulfate 200 mg three times daily as the most cost-effective and appropriate initial treatment 1
• Alternative oral formulations (ferrous gluconate or ferrous fumarate) are equally effective if ferrous sulfate is not tolerated 1
• Consider adding ascorbic acid (vitamin C) to enhance iron absorption if response is poor 1
• Liquid preparations may be better tolerated when tablets cause side effects 1

Treatment Goals and Duration

• Aim to restore hemoglobin levels and MCV to normal AND replenish iron stores 1
• Continue iron supplementation for 3 months after correction of anemia to adequately replenish iron stores 1
• Expect hemoglobin to rise by 2 g/dL after 3-4 weeks of treatment 1

When to Consider Intravenous Iron

Intravenous iron should be reserved for specific situations and is not first-line therapy in uncomplicated iron deficiency anemia 1:

• Intolerance to at least two different oral iron preparations 1
• Non-compliance with oral therapy 1
• Intestinal malabsorption conditions 2
• Active inflammatory bowel disease with compromised absorption 1
• Hemoglobin below 100 g/L (10 g/dL) in patients with inflammatory conditions 1
• Failure to respond to adequate oral iron therapy despite compliance 3, 2

Monitoring Response to Treatment

Initial Follow-Up

• Check hemoglobin at 3-4 weeks to confirm response (should increase by 1-2 g/dL) 1, 4
• Failure to respond indicates: poor compliance, continued blood loss, malabsorption, or misdiagnosis 1

Long-Term Monitoring

• Monitor hemoglobin and red cell indices every 3 months for the first year, then again after one additional year 1
• Check ferritin if hemoglobin or MCV falls below normal during follow-up 1
• Further investigation is only necessary if hemoglobin and MCV cannot be maintained with iron supplementation 1

Diagnostic Workup Considerations

While treatment should begin immediately, the underlying cause must be identified:

Essential Investigations

• Complete iron studies (serum ferritin, transferrin saturation, total iron-binding capacity) to confirm iron deficiency 1, 2
• Celiac disease screening with transglutaminase antibody (IgA type) and total IgA level 1, 2
• Bidirectional endoscopy (gastroscopy and colonoscopy) in most adults, particularly men and postmenopausal women 1, 2, 5

Special Population Considerations

• Premenopausal women under 40 years: May not require endoscopy if menstrual loss is the likely cause 1, 2
• Patients over 45 years: Should undergo full gastrointestinal evaluation due to increased risk of malignancy 1
• Renal disease (GFR <30 mL/min/1.73 m²): Requires workup for anemia including iron studies when hemoglobin <12 g/dL (women) or <13 g/dL (men) 1

Common Pitfalls to Avoid

• Do not use parenteral iron as first-line therapy unless specific contraindications to oral iron exist—it is more expensive, painful when given intramuscularly, and carries risk of anaphylaxis 1
• Do not stop iron supplementation when hemoglobin normalizes—continue for 3 months to replenish stores 1
• Do not assume treatment failure at 2 weeks—allow 3-4 weeks before reassessing response 1
• Do not perform fecal occult blood testing—it is insensitive and non-specific for iron deficiency anemia workup 1