Ferrous Sulfate Dosing for a 6-Year-Old Child with Anemia
For this 20 kg, 6-year-old child with anemia, give 60 mg of elemental iron daily as ferrous sulfate, administered once daily between meals.
Recommended Dosing Regimen
The standard therapeutic dose is 3 mg/kg/day of elemental iron, which for a 20 kg child equals 60 mg of elemental iron daily 1, 2. This weight-based calculation balances efficacy with tolerability and represents the evidence-based standard for pediatric iron-deficiency anemia treatment 1.
Practical Formulation Guidance
- Ferrous sulfate drops (25 mg elemental iron/mL): Give approximately 2.4 mL once daily 1
- Ferrous sulfate tablets (65 mg elemental iron per 200 mg tablet): If the child can swallow tablets, give one tablet daily 3
- The once-daily regimen is as effective as divided dosing and may improve adherence 4, 2
Administration Instructions
Administer iron between meals (on an empty stomach) to maximize absorption, as food can reduce iron bioavailability by up to 50% 1, 5. Specifically:
- Give at least 2 hours before or 1 hour after meals 5
- Avoid concurrent administration with dairy products, tea, or coffee, which significantly inhibit absorption 5
Managing Gastrointestinal Side Effects
If gastrointestinal symptoms occur, consider dividing the total daily dose into smaller amounts rather than discontinuing therapy 5. However, recent evidence demonstrates that low-dose ferrous sulfate (3 mg/kg/day) is well-tolerated, with fewer side effects than higher traditional doses 2, 6.
Treatment Duration and Monitoring
Continue treatment for 4 weeks, then recheck hemoglobin 1:
- If hemoglobin increases by ≥1 g/dL after 4 weeks, this confirms iron-deficiency anemia and treatment should continue for an additional 2 months (total ~3 months) to replenish iron stores 1
- After completing the full course, perform follow-up hemoglobin assessment, with reassessment approximately 6 months later 1
Non-Response Protocol
If anemia does not improve after 4 weeks despite confirmed adherence, obtain further laboratory evaluation including MCV, RDW, and serum ferritin to exclude malabsorption, ongoing blood loss, or alternative diagnoses 1, 5. Consider intravenous iron if malabsorption is suspected 5.
Evidence Supporting Low-Dose Once-Daily Therapy
The most recent high-quality evidence demonstrates that 3 mg/kg/day ferrous sulfate given once daily is superior to iron polysaccharide complex and achieves complete resolution of iron-deficiency anemia in a significant proportion of children 2. This 2017 JAMA trial showed:
- Greater increase in hemoglobin (mean increase to 11.9 g/dL vs 11.1 g/dL, difference 1.0 g/dL, P<0.001) 2
- Higher rate of complete IDA resolution (29% vs 6%, P=0.04) 2
- Better ferritin repletion (median increase to 15.6 vs 7.5 ng/mL, P<0.001) 2
Additional studies confirm that once-daily dosing achieves similar efficacy to three-times-daily regimens without increased side effects 4, 6.
Important Clinical Caveats
- Dietary counseling should accompany iron therapy to address underlying inadequate dietary iron intake 1
- Mild gastrointestinal symptoms (nausea, diarrhea) should not necessarily prompt discontinuation 1
- Systemic iron toxicity with hepatocellular damage has been reported with excessive iron administration in pediatric patients, emphasizing the importance of proper weight-based dosing 1
- The adult dose of ferrous sulfate (200 mg twice daily) is inappropriate for children and should never be used 3