What is the treatment plan for a 17-year-old female with iron deficiency anemia?

Treatment Plan for Iron Deficiency Anemia in a 17-Year-Old Female

Immediate Treatment Recommendation

Start ferrous sulfate 325 mg (65 mg elemental iron) once daily, taken with 500 mg vitamin C, and continue for 3 months after hemoglobin normalizes to fully replenish iron stores. 1, 2

The proposed plan of ferrous sulfate three times weekly is suboptimal. While the patient's labs show clear iron deficiency (ferritin 12 ng/mL, iron saturation 8%, low MCH and MCHC), the dosing frequency needs adjustment based on current evidence.

Optimal Dosing Strategy

• Once-daily dosing is superior to multiple daily doses or three-times-weekly dosing because it improves tolerability while maintaining effectiveness 1, 3
• Research demonstrates that alternate-day dosing (every other day) actually increases iron absorption by 21.8% compared to 16.3% with consecutive daily dosing, as it prevents hepcidin elevation that blocks subsequent iron absorption 3
• The three-times-weekly regimen prescribed lacks evidence support and may result in inadequate iron repletion 1

Recommended dosing adjustment: Either ferrous sulfate 325 mg once daily OR ferrous sulfate 325 mg every other day (alternate days) 1, 3

Vitamin C Co-Administration

• Vitamin C 500 mg should be taken simultaneously with each iron dose to enhance absorption, particularly critical given the severely low iron saturation of 8% 2, 1
• Taking vitamin C with iron is especially important when response is suboptimal 2, 1

Timing and Food Interactions

• Take iron on an empty stomach for optimal absorption, though taking with food is acceptable if gastrointestinal side effects occur 1
• Avoid calcium, dairy products, proton pump inhibitors, and antacids within 2 hours of iron dosing as these significantly impair absorption 1

Duration of Therapy

• Continue iron supplementation for 3 months AFTER hemoglobin and ferritin normalize, not just until anemia corrects 2, 1
• This extended duration is essential to replenish depleted iron stores (current ferritin is only 12 ng/mL) 2, 1

Expected Response and Monitoring Timeline

• Hemoglobin should increase by approximately 2 g/dL after 3-4 weeks of treatment 1, 4
• Recheck CBC and ferritin at 4 weeks to assess response—if hemoglobin fails to rise by at least 1 g/dL, reassess for non-adherence, ongoing blood loss, or malabsorption 2, 1
• After initial response, monitor hemoglobin and red cell indices every 3 months for the first year, then again after another year 2, 1

Evaluation of Underlying Cause

The GI referral is appropriate given the patient's age and severity of iron deficiency. Key considerations:

• Heavy menstrual bleeding is the most common cause in adolescent females, affecting approximately 10% of menstruating women and representing a critical risk factor 2
• Adolescent females aged 12-17 years have increased iron requirements due to rapid growth and menstruation 2
• The elevated alkaline phosphatase (125 IU/L) may reflect normal adolescent bone growth rather than pathology 1
• GI evaluation should proceed as planned to exclude celiac disease, inflammatory bowel disease, or occult bleeding 1, 4

When to Consider Intravenous Iron

Switch to IV iron if: 1, 4

• No hemoglobin response after 4 weeks despite adherence
• Intolerance to at least two different oral iron preparations
• Celiac disease or inflammatory bowel disease diagnosed with active inflammation
• Ongoing blood loss exceeding oral replacement capacity

Common Pitfalls to Avoid

• Do not stop iron when hemoglobin normalizes—continue for 3 months to replenish stores 2, 1
• Do not use multiple daily doses—this increases side effects without improving efficacy and elevates hepcidin, blocking absorption 1, 3
• Do not continue oral iron beyond 4-6 weeks without documented response—reassess and consider IV iron if no improvement 1
• Do not overlook vitamin C supplementation—absorption enhancement is critical with severe deficiency 2, 1
• Do not fail to address menstrual blood loss—consider gynecology referral if menorrhagia suspected 2

Dietary Counseling

• Increase dietary iron from red meat, leafy greens, beans, and iron-fortified foods 2
• Emphasize that dietary changes alone cannot correct established iron deficiency anemia—supplementation is mandatory 2, 1

Alternative Oral Formulations

If ferrous sulfate is not tolerated, switch to ferrous gluconate or ferrous fumarate, which are equally effective 2, 1, 4