What is the recommended treatment for iron deficiency?

Treatment of Iron Deficiency

Start with oral ferrous sulfate 200 mg (65 mg elemental iron) once daily, continue for 3 months after hemoglobin normalizes, and reserve intravenous iron for specific clinical scenarios including intolerance, malabsorption, or chronic inflammatory conditions. 1

First-Line Oral Iron Therapy

The initial treatment should be one tablet per day of ferrous sulfate, ferrous fumarate, or ferrous gluconate. 1 Among these options, ferrous sulfate 200 mg once daily (containing approximately 65 mg elemental iron) represents the gold standard—it is the most simple, effective, and cost-efficient preparation available. 2, 3

Dosing Strategy

• Begin with 100-200 mg elemental iron daily in divided doses for standard treatment 1
• For pregnant women, start with low-dose supplementation (30 mg/day) at the first prenatal visit, escalating to 60-120 mg/day if anemia develops 1
• Do not defer iron therapy while awaiting diagnostic investigations unless colonoscopy is imminent 1

Duration and Monitoring

• Monitor hemoglobin response within the first 4 weeks—expect approximately 2 g/dL rise after 3-4 weeks 2, 4
• Continue treatment for approximately 3 months after hemoglobin normalization to adequately replenish bone marrow iron stores 1, 2
• After restoration, monitor blood counts every 6 months initially to detect recurrence 2

Managing Oral Iron Intolerance

If standard daily dosing causes gastrointestinal side effects (constipation, diarrhea, nausea):

• Reduce to one tablet every other day—recent evidence suggests better iron absorption and fewer adverse effects with alternate-day dosing 1
• Switch to liquid iron preparations, which may be better tolerated 2
• Consider slow-release ferrous sulfate formulations for improved tolerability 2
• Add ascorbic acid (vitamin C) to enhance absorption 2
• Take supplements on an empty stomach to maximize absorption 2

Intravenous Iron Therapy

Reserve parenteral iron for specific clinical indications—it should not be first-line therapy when oral iron would be effective. 2, 3

Clear Indications for IV Iron

• Intolerance to at least two different oral iron preparations 2
• Poor compliance with oral therapy 2
• Malabsorption conditions: celiac disease, post-bariatric surgery, inflammatory bowel disease 1, 2
• Chronic inflammatory conditions: chronic kidney disease, chronic heart failure 1
• Ongoing blood loss requiring rapid repletion 2, 4
• Second and third trimesters of pregnancy when rapid correction is needed 4

IV Iron Administration

• Ferric carboxymaltose and ferric derisomaltose allow high doses (500-1000 mg) in a single 15-minute infusion 1, 3
• Iron sucrose and ferric gluconate require multiple administrations but are widely used 1
• Always administer in medical facilities with trained staff to manage rare hypersensitivity reactions (<1:250,000 administrations) 1
• Monitor phosphate levels, particularly with ferric carboxymaltose, due to hypophosphatemia risk 3
• Avoid high molecular weight iron dextran due to highest reaction risk 1

Special Population Considerations

Inflammatory Bowel Disease

• Intolerance and malabsorption of oral iron are particular problems in IBD 1
• Parenteral iron may be required, especially when disease is active 1

Chronic Heart Failure

• Parenteral iron may improve symptoms and quality of life in heart failure with functional iron deficiency 1
• Refer to specialist guidelines for management 1

Athletes and Menstruating Women

• Require higher daily iron intake (18-22 mg/day) to maintain adequate stores 1, 2
• Consider empiric supplementation for high-risk athletes (vegetarian/vegan diets, high-impact sports, heavy menstrual bleeding) 1

Elderly Patients

• Iron deficiency is often multifactorial in this population 1
• Carefully weigh risks and benefits of invasive investigations in those with major comorbidities 1

When Oral Iron Fails

If anemia does not respond after 4 weeks despite compliance and absence of acute illness:

• Perform additional laboratory tests: MCV, RDW, serum ferritin 1
• Consider thalassemia minor or sickle cell trait in patients of African, Mediterranean, or Southeast Asian ancestry 1
• Evaluate for continued blood loss, malabsorption, or misdiagnosis 2
• In patients with negative bidirectional endoscopy and inadequate response, investigate small bowel and renal tract 1

Critical Pitfalls to Avoid

• Never delay iron therapy while awaiting investigations (unless colonoscopy is imminent) 1
• Never discontinue therapy prematurely—stopping when hemoglobin normalizes without replenishing stores leads to rapid recurrence 1, 2
• Never use parenteral iron as first-line when oral iron would suffice—reserve for specific indications 2, 3
• Never supplement iron when ferritin is normal or elevated—this is potentially harmful and not recommended 1
• Never transfuse packed red cells without continuing iron therapy post-transfusion 1

Long-Term Management

• Long-term iron replacement may be appropriate when the cause of recurrent deficiency is unknown or irreversible 1
• Hemoglobin normalizes with iron therapy in most cases, but recurrence occurs in a minority on long-term follow-up 1
• Do not recheck ferritin levels earlier than 8-10 weeks after IV iron infusion, as levels are falsely elevated 1