What dose of the 15 mg/5 mL iron preparation should be given to a 129‑lb (≈58 kg) child to deliver 15 mg elemental iron daily?

Dosing Calculation for 15 mg/5 mL Iron Preparation

Give 5 mL once daily to deliver 15 mg of elemental iron. This straightforward calculation (15 mg ÷ 3 mg/mL = 5 mL) provides the exact therapeutic dose recommended by CDC guidelines for treating iron-deficiency anemia in children 1.

Dosing Rationale

• The preparation contains 3 mg elemental iron per mL (15 mg per 5 mL) 1
• To deliver 15 mg elemental iron daily, the child needs 5 mL of the preparation once daily 1
• This 15 mg daily dose represents approximately 0.26 mg/kg/day for a 129-lb (58 kg) child, which is below the standard therapeutic dose of 3 mg/kg/day (≈174 mg/day for this weight) used for treating iron-deficiency anemia 1

Important Clinical Context

This dose (15 mg/day) appears to be a prophylactic or maintenance dose rather than a therapeutic dose for treating active iron-deficiency anemia. For context:

• Therapeutic dosing for iron-deficiency anemia treatment requires 3 mg/kg/day of elemental iron, which would be approximately 174 mg/day (≈58 mL of this preparation) for a 58 kg child 1
• Prophylactic dosing for preventing iron deficiency in healthy children typically uses lower doses, such as 1-2 mg/kg/day for marginally low-birth-weight infants 2
• Studies show that even doses as low as 5-10 mg/day added to meals can effectively reduce anemia prevalence in preschool children 3

Administration Guidelines

• Administer between meals (on an empty stomach) to maximize iron absorption, as concurrent food markedly reduces bioavailability 1
• If gastrointestinal side effects occur (nausea, mild cramping), the dose may be given with a small amount of food, though this reduces absorption 1
• Continue dietary counseling to address underlying inadequate iron intake 1

Monitoring Recommendations

• If this is therapeutic treatment for anemia, recheck hemoglobin after 4 weeks to confirm adequate response (expected increase ≥1 g/dL) 1
• If treating confirmed iron-deficiency anemia with this lower dose, response may be slower than with standard 3 mg/kg/day dosing 1
• Monitor for iron overload with regular ferritin and hemoglobin checks if supplementation continues long-term 4, 1

Common Pitfall

The most critical error would be using this 15 mg/day dose to treat active iron-deficiency anemia when therapeutic dosing (3 mg/kg/day ≈ 174 mg/day for this child) is indicated. Verify whether the goal is prophylaxis/maintenance (15 mg appropriate) versus treatment of documented anemia (requires higher dosing) 1.