What is the treatment for a patient with iron deficiency anemia, indicated by low hemoglobin, iron saturation, and ferritin levels?

Treatment of Iron Deficiency Anemia

All patients with iron deficiency anemia (hemoglobin 11.8 g/dL, ferritin 10 ng/mL, iron saturation 9%) should receive iron supplementation to correct anemia and replenish body stores, with oral ferrous sulfate 325 mg daily (or on alternate days) as first-line therapy. 1, 2

Immediate Treatment Approach

Start oral iron supplementation immediately:

• Ferrous sulfate 325 mg (65 mg elemental iron) once daily or on alternate days 3, 2
• Alternative formulations include ferrous gluconate or ferrous fumarate if ferrous sulfate is not tolerated 1
• Take on an empty stomach for optimal absorption, or with meals if gastrointestinal side effects occur 1
• Co-administer with 500 mg vitamin C to enhance absorption 1
• Avoid tea and coffee around meal times as they impair iron absorption 1

Expected Response and Monitoring

Hemoglobin should increase by 1-2 g/dL within 3-4 weeks of starting therapy: 1, 4

• If no response occurs, consider malabsorption, continued blood loss, non-compliance, or misdiagnosis 1
• Continue iron supplementation for 3 months after correction of anemia to replenish iron stores 1
• Monitor hemoglobin and ferritin every 3 months for one year, then annually 1

When to Consider Intravenous Iron

Intravenous iron is indicated when: 1, 2

• Intolerance to at least two oral iron preparations occurs 1
• Malabsorption is present (celiac disease, post-bariatric surgery, inflammatory bowel disease) 1, 2
• Ongoing blood loss continues 2
• Oral iron fails after 4 weeks of therapy 1
• Chronic inflammatory conditions exist (chronic kidney disease, heart failure, inflammatory bowel disease, cancer) 1, 2

Available IV formulations include iron sucrose, ferric gluconate, ferric carboxymaltose, and low molecular weight iron dextran, with similar safety and efficacy profiles 1. Iron dextran requires a 25 mg test dose due to anaphylaxis risk 1, while other formulations do not require test dosing 1.

Investigation for Underlying Cause

The following evaluation is mandatory to identify the source of iron loss:

For all patients:

• Review dietary iron intake and assess for inadequate consumption 2
• Evaluate medication use, particularly NSAIDs and proton pump inhibitors 2, 4
• Screen for celiac disease if malabsorption is suspected 1
• Test for Helicobacter pylori infection 1

For premenopausal women:

• Assess menstrual blood loss patterns 1
• Consider gynecologic evaluation if menorrhagia is present 1

For men and postmenopausal women:

• Bidirectional endoscopy (upper endoscopy and colonoscopy) is mandatory to exclude gastrointestinal malignancy 1, 4
• 9% of patients over 65 years with iron deficiency anemia have gastrointestinal cancer 4
• Begin with colonoscopy if patient is over 50 years old 4

Common Pitfalls to Avoid

Gastrointestinal side effects (constipation, nausea, diarrhea) are common with oral iron: 1

• These side effects are the primary cause of non-compliance 1
• Alternate-day dosing may improve absorption and reduce side effects compared to daily dosing 1
• Switching to a different oral iron formulation may improve tolerance 1

Do not delay investigation in high-risk populations:

• Men and postmenopausal women require endoscopic evaluation regardless of response to iron therapy 1, 4
• Failure to investigate can miss gastrointestinal malignancy 4

Avoid premature use of intravenous iron:

• Oral iron should be attempted first unless specific contraindications exist 1, 2
• Intravenous iron carries risks including anaphylactoid reactions, though these are rare (<1:250,000 with modern formulations) 1

Target Goals

Treatment goals are: 1

• Restore hemoglobin to normal (≥12 g/dL in women, ≥13 g/dL in men) 1
• Normalize MCV 1
• Replenish iron stores (ferritin >30 ng/mL, transferrin saturation >20%) 1
• Retest after 8-10 weeks to assess treatment success 1