Safe Liquid Iron Dosing for a 13-Year-Old Child
For a healthy 13-year-old adolescent, the safe dose of liquid elemental iron (ferrous sulfate) is 2 to 3 mg/kg/day of elemental iron, divided into 2-3 doses throughout the day. 1
Standard Dosing Guidelines
- The pediatric standard is 2-3 mg/kg/day of elemental iron in divided doses, as established by the National Kidney Foundation guidelines 1
- For a 13-year-old weighing approximately 40-50 kg, this translates to roughly 80-150 mg of elemental iron per day total 1
- This dose should be divided into 2-3 administrations throughout the day to improve tolerance and absorption 1
Treatment Context: Dosing Varies by Indication
The 2-3 mg/kg/day range applies to maintenance supplementation or chronic kidney disease, but therapeutic dosing differs:
- For treatment of iron-deficiency anemia: 3 mg/kg/day is the standard therapeutic dose, continued for 4 weeks initially, then 2 additional months if responsive 2
- For prevention in at-risk populations: Lower doses (1-2 mg/kg/day) may suffice 3
- Maximum therapeutic dosing: Up to 6 mg/kg/day has been studied in children, though this higher dose increases gastrointestinal side effects without necessarily improving outcomes 4, 5
Optimal Administration Practices
- Give iron between meals (on an empty stomach) to maximize absorption, as food can reduce absorption by up to 50% 1, 2, 6
- If gastrointestinal side effects occur, start with a lower dose and gradually increase, or give smaller, more frequent doses 1, 6
- Avoid taking iron within 2 hours before or 1 hour after meals for optimal absorption 1
- Consider bedtime administration if daytime dosing causes intolerance 1
Formulation Considerations for Liquid Iron
- Ferrous sulfate is the preferred formulation due to better clinical response, fewer side effects, and cost-effectiveness (65 mg elemental iron per 325 mg tablet equivalent) 3
- Liquid preparations are appropriate for pediatric patients and provide known amounts of elemental iron 1
- Ferrous gluconate may be better tolerated in children with constipation, though it contains less elemental iron (35 mg per 325 mg equivalent) 6
Critical Safety Thresholds
- Doses below 40 mg/kg of elemental iron as a single ingestion are generally safe and can be observed at home 7
- Ingestions of 40 mg/kg or greater require immediate medical evaluation due to toxicity risk 7
- For a 40 kg adolescent, this safety threshold is approximately 1,600 mg of elemental iron in a single dose—far exceeding therapeutic daily dosing 7
Common Pitfalls to Avoid
- Do not use aluminum-based phosphate binders concurrently, as they reduce iron absorption 1
- Excessive cow's milk consumption (>24 oz daily) can interfere with iron absorption 3
- Avoid tea, coffee, or calcium-containing foods within 2 hours of iron administration 6
- Vitamin C may enhance absorption when taken with iron, though ascorbic acid does not improve ferrous iron absorption in all contexts 1, 6
Monitoring Response
- Recheck hemoglobin after 4 weeks of therapeutic dosing; expect an increase of ≥1 g/dL if iron-deficiency anemia is present 2, 3
- Continue treatment for 2-3 months total to replenish iron stores after anemia correction 2, 8
- Monitor for gastrointestinal side effects (nausea, vomiting, diarrhea), which are common but should not automatically prompt discontinuation unless severe 2