What is the best first‑line oral iron supplement and dosing regimen for a 5‑year‑old girl with iron‑deficiency anemia?

Oral Iron Supplementation for a 5-Year-Old with Iron-Deficiency Anemia

For a 5-year-old girl with iron-deficiency anemia, prescribe 3 mg/kg/day of elemental iron using ferrous sulfate, ferrous fumarate, or ferrous gluconate, given as a single morning dose on an empty stomach. 1

Recommended Iron Formulation

Use ionic iron salts (ferrous sulfate, ferrous fumarate, or ferrous gluconate) as first-line therapy because they are the most cost-effective, provide known amounts of elemental iron, and have well-established efficacy. 1

• Ferrous sulfate 200 mg tablets contain 65 mg elemental iron 1
• Ferrous fumarate 210 mg tablets contain 69 mg elemental iron 1
• Ferrous gluconate 300 mg tablets contain 37 mg elemental iron 1
• Liquid iron preparations are more practical for young children than solid dose forms 1

Iron polysaccharide formulations are more expensive and offer no advantage in tolerability or effectiveness compared to ionic iron salts. 1

Dosing Regimen

The standard pediatric dose is 2-3 mg/kg/day of elemental iron. 1 For treatment of confirmed iron-deficiency anemia, prescribe 3 mg/kg/day of elemental iron. 1

Optimal Timing and Frequency

• Administer iron on an empty stomach (between meals) to maximize absorption 1
• Give as a single morning dose rather than divided doses, as recent evidence shows once-daily dosing achieves similar total iron absorption with better tolerance 1
• Food consumed within 2 hours before or 1 hour after iron reduces absorption by up to 50% 1

Practical Calculation Example

For a 5-year-old weighing approximately 18 kg:

• Target dose: 3 mg/kg/day × 18 kg = 54 mg elemental iron daily
• This could be achieved with approximately 3-4 mL of ferrous sulfate drops (125 mg/mL = 25 mg elemental iron/mL) 1

Monitoring and Duration

Recheck hemoglobin at 4 weeks. 1 An increase in hemoglobin ≥1 g/dL or hematocrit ≥3% confirms the diagnosis and adequate response. 1

• If response is adequate, continue iron therapy for 2 additional months (total 3 months) to replenish iron stores 1
• Reassess hemoglobin approximately 6 months after completing treatment 1

Managing Poor Tolerance

If gastrointestinal side effects occur (nausea, abdominal discomfort, constipation):

• Start with a lower dose and increase gradually to the target dose 1
• Consider alternate-day dosing with a slightly higher dose (e.g., 5-6 mg/kg every other day), which may improve tolerance while maintaining efficacy 1
• Try administering at bedtime 1
• Switch to a different ferrous salt formulation 1

When to Consider Parenteral Iron

Consider intravenous iron if:

• No hemoglobin response after 4 weeks despite documented compliance 1
• Severe intolerance to oral iron despite dose adjustments 1
• Malabsorption is suspected 1

Common Pitfalls to Avoid

• Do not use modified-release preparations in children—they are less suitable and may release iron beyond the duodenum where absorption is poor 1
• Do not add ascorbic acid routinely—it does not improve ferrous iron absorption in children 1
• Avoid giving iron with calcium-containing foods or aluminum-based medications, which reduce absorption 1
• Do not prescribe multivitamins with low iron content (typically ≤14 mg) as primary treatment—they are insufficient for treating anemia 1

Dietary Counseling

Counsel parents to limit cow's milk intake to ≤24 oz daily and encourage iron-rich foods (meat, iron-fortified cereals) and vitamin C-rich foods with meals to enhance absorption. 1