What are the treatment options for iron deficiency anemia, including doses, routes, and regimens?

Treatment of Iron Deficiency Anemia: Doses, Routes, and Regimens

For iron deficiency anemia treatment, begin with oral ferrous sulfate at 60-120 mg elemental iron once daily in the morning, and if inadequate response or intolerance occurs, switch to intravenous iron with ferric carboxymaltose 750 mg given as two doses separated by at least 7 days. 1, 2, 3

Diagnosis Confirmation

Before initiating treatment, confirm iron deficiency anemia with:

• Ferritin <30 μg/L in patients without inflammation
• Ferritin <100 μg/L in patients with inflammation
• Transferrin saturation <20%
• Hemoglobin <13.0 g/dL in men, <12.0 g/dL in non-pregnant women 2

Oral Iron Therapy

First-Line Approach

• Formulation: Ferrous sulfate (preferred due to cost-effectiveness) 1
• Dosing: 60-120 mg elemental iron once daily 1, 2
• Timing: Morning administration as a single dose (not divided) 1, 4
• Frequency: Daily or alternate-day dosing (alternate-day may improve absorption) 1, 4
• Duration: Continue for 2-3 months after hemoglobin normalizes 2
• Enhancers: Add vitamin C to improve absorption 1

Practical Tips for Oral Iron

• Avoid taking with meals, tea, coffee, or calcium-containing foods
• Take on an empty stomach if tolerated
• If gastrointestinal side effects occur, consider:
  • Reducing dose
  • Switching to alternate-day dosing
  • Taking with a small amount of food 1, 4

Intravenous Iron Therapy

Indications for IV Iron

• Intolerance to oral iron (gastrointestinal side effects)
• Failure to respond to oral iron (ferritin levels not improving)
• Conditions where oral iron is unlikely to be absorbed:
  • Active inflammatory bowel disease
  • Gastric bypass surgery
  • Chronic kidney disease
  • Severe anemia (Hb <10 g/dL) requiring rapid correction 1, 2

IV Iron Formulations and Dosing

1. Ferric Carboxymaltose (Injectafer):

   • For patients ≥50 kg: 750 mg IV in two doses separated by at least 7 days (total 1,500 mg)
   • For patients <50 kg: 15 mg/kg IV in two doses separated by at least 7 days 3

2. Other IV Iron Formulations:

   • Iron sucrose: 200 mg per session, multiple sessions required
   • Ferric gluconate: 125 mg per session, multiple sessions required
   • Iron dextran: Total dose infusion possible but higher risk of reactions 1

Administration of IV Iron

• Ferric carboxymaltose can be given as:
  • Slow IV push at 100 mg/minute
  • Infusion (diluted in 250 mL normal saline) over at least 15 minutes 3
• Monitor for infusion reactions during administration
• Avoid extravasation as it may cause long-lasting brown discoloration 3

Monitoring Response to Treatment

• Check hemoglobin after 4 weeks of treatment
  • Expected response: Increase of approximately 1-2 g/dL 2
• Check iron studies (ferritin, transferrin saturation) after 8-10 weeks 1
• Target ferritin levels: 50-100 μg/L indicates successful repletion 1
• Continue treatment for 2-3 months after hemoglobin normalizes to replenish iron stores 2, 5
• Monitor periodically (every 3-6 months) after treatment completion if at risk for recurrence 2

Special Considerations

Severe Anemia (Hb <8 g/dL)

• Consider direct initiation of IV iron therapy for faster correction 2
• Blood transfusion may be considered if symptomatic or hemodynamically unstable

Pregnancy

• First trimester: Oral iron preferred
• Second/third trimester: IV iron may be considered if needed 2

Chronic Kidney Disease

• IV iron often preferred due to reduced oral absorption 1

Inflammatory Conditions

• IV iron may be more effective than oral iron
• Treat underlying inflammation when possible 1, 2

Common Pitfalls to Avoid

1. Inadequate dosing or duration: Many patients stop treatment once hemoglobin normalizes but before iron stores are replenished 5

2. Ignoring underlying causes: Always investigate and address the cause of iron deficiency (e.g., bleeding, malabsorption) 6

3. Inappropriate monitoring: Checking ferritin too early after IV iron can give falsely elevated results 1

4. Overlooking inflammation: Ferritin is an acute phase reactant and may be falsely normal or elevated in inflammatory states 2

5. Continuing ineffective therapy: If no response after 4 weeks of oral iron, consider switching to IV iron rather than persisting with an ineffective approach 2, 7