What is the recommended prescription for a patient with iron deficiency anemia?

Prescription for Iron Deficiency Anemia

Start with ferrous sulfate 200 mg (65 mg elemental iron) taken once daily in the morning on an empty stomach, combined with vitamin C to enhance absorption. 1, 2

Initial Prescription Details

Ferrous sulfate 200 mg tablet, take ONE tablet by mouth ONCE DAILY in the morning on an empty stomach. 1

• Add vitamin C (ascorbic acid) 250-500 mg with each dose to improve iron absorption 1
• If gastrointestinal side effects occur, switch to alternate-day dosing (ferrous sulfate 200 mg every other day), which maintains similar iron absorption with significantly fewer side effects 1, 3
• Continue treatment for 3 months after hemoglobin normalizes to replenish iron stores 1

Monitoring Response

Check hemoglobin at 2 weeks: 1

• Expect hemoglobin rise of at least 10 g/L (1 g/dL) after 2 weeks of daily oral therapy 1
• Absence of this rise predicts treatment failure with 90% sensitivity and should prompt switching to intravenous iron 1
• Continue monitoring hemoglobin every 4 weeks until normalized 1

When to Switch to Intravenous Iron

Use IV iron immediately instead of oral iron if: 1

• Active inflammatory bowel disease with inflammation present 1
• Post-bariatric surgery (especially Roux-en-Y gastric bypass) 1
• Chronic kidney disease on dialysis 1
• Chronic heart failure with ferritin <100 μg/L or transferrin saturation <20% 1
• Celiac disease with poor absorption 1
• Intolerance to at least two different oral iron formulations 1
• No hemoglobin response after 2 weeks of adequate oral therapy 1
• Ongoing significant blood loss 1
• Second or third trimester of pregnancy with inadequate oral response 4

For IV iron, prescribe: 1

• Ferric carboxymaltose 1000 mg IV as single dose (preferred for convenience) OR
• Low-molecular-weight iron dextran 1000 mg IV as single dose (most cost-effective at $405 vs $3470 for ferric carboxymaltose) 1
• Avoid ferric carboxymaltose if repeated dosing needed due to hypophosphatemia risk 1

Special Populations

Inflammatory Bowel Disease: 1

• Maximum 100 mg elemental iron daily if disease is inactive 1
• Use IV iron if active inflammation present, as systemic inflammation blocks oral iron absorption 1

Concurrent Proton Pump Inhibitor Use: 5

• Patients on PPIs have markedly reduced oral iron absorption (only 16% achieve normal hemoglobin response) 5
• Consider stopping PPI if medically appropriate, or use IV iron 5

Pregnancy: 1, 4

• Daily folic acid 400 μg (or 5 mg if on sulfasalazine or with small bowel disease) 1
• IV iron preferred in second and third trimesters if oral iron inadequate 4

Cost Considerations

• Ferrous sulfate 200 mg: $1.00 per 28 days (most cost-effective) 1, 2
• Ferric maltol: $47.60 per 28 days (alternative if traditional salts not tolerated) 1
• IV iron: $405-$3896 per treatment course depending on formulation 1

Common Pitfalls to Avoid

• Do not prescribe three times daily dosing - once daily or alternate-day dosing maximizes absorption and minimizes side effects 1, 3
• Do not give afternoon/evening doses - morning dosing optimizes absorption due to circadian hepcidin patterns 3
• Do not use modified-release preparations - they are less suitable for prescribing 1
• Do not switch between different ferrous salts for intolerance - this is not evidence-based; switch to alternate-day dosing, ferric maltol, or IV iron instead 1
• Do not continue ineffective oral therapy - if no hemoglobin rise after 2 weeks, switch to IV iron 1