What is the recommended dose of ferrous sulfate (iron supplement) for pediatric patients with iron deficiency anemia?

Ferrous Sulfate Dosing in Pediatric Iron Deficiency Anemia

For treatment of iron deficiency anemia in children, administer ferrous sulfate at 2-3 mg/kg/day of elemental iron divided into 2-3 doses, with a maximum treatment dose of 6 mg/kg/day for confirmed IDA. 1, 2

Standard Dosing by Clinical Scenario

Treatment of Confirmed Iron Deficiency Anemia

• Administer 3 mg/kg/day of elemental iron for active treatment of confirmed IDA 1
• Divide the total daily dose into 2-3 administrations throughout the day 2
• The upper limit for treatment is 6 mg/kg/day, though most children respond adequately to 2-3 mg/kg/day 1, 3
• Ferrous sulfate contains 65 mg of elemental iron per 325 mg tablet, making dose calculations straightforward 1

Prophylactic Dosing for At-Risk Infants

• Full-term breastfed infants: 1 mg/kg/day starting at 6 months if insufficient iron from supplementary foods 1
• Preterm or low birthweight breastfed infants: 2-4 mg/kg/day (maximum 15 mg/day) starting at 1 month of age until 12 months 1
• When exclusive breastfeeding stops, provide approximately 1 mg/kg/day from supplementary foods or drops 1

Special Populations

• Children with chronic kidney disease: 2-3 mg/kg/day of elemental iron in divided doses 1
• Children on parenteral nutrition unable to tolerate enteral iron: 50-100 μg/kg/day IV up to maximum 5 mg/day 1

Administration Guidelines for Optimal Absorption

Give iron between meals or at bedtime on an empty stomach to maximize absorption 1, 2

• Avoid food within 2 hours before or 1 hour after iron administration, as food reduces absorption by up to 50% 1, 2
• Separate aluminum-based phosphate binders from iron dosing as they reduce absorption 1, 2
• Include vitamin C-rich foods with meals on non-dosing times to enhance overall iron absorption 1
• Limit cow's milk to less than 24 oz daily, as excessive consumption interferes with iron absorption 1

Formulation Selection

Ferrous sulfate is the preferred formulation due to better clinical response, fewer side effects, and superior cost-effectiveness compared to other iron preparations 1, 4

• Liquid iron preparations are more appropriate for young children than tablets 2
• Ferrous sulfate demonstrated higher hemoglobin levels and fewer residual complaints compared to iron polymaltose complex in head-to-head comparison 4

Managing Side Effects

If gastrointestinal side effects occur:

• Reduce to smaller, more frequent doses rather than discontinuing therapy 2
• Consider alternate-day dosing as a compromise 2
• Start with a lower dose and gradually titrate up to target to improve tolerance 2
• Mild gastrointestinal symptoms should not prompt discontinuation 2

Monitoring Response to Treatment

Measure hemoglobin after 1 month of treatment to assess response 1

• Adequate response is defined as hemoglobin rise ≥1.0 g/dL with normalization of ferritin and transferrin saturation 1
• Continue iron supplementation for an appropriate duration after anemia resolution, though guidelines show variability in recommended duration (0-3 months) 5
• If no response despite documented compliance, evaluate further with MCV, RDW, and serum ferritin 2

Critical Safety Considerations

• Never exceed recommended doses, as hepatocellular damage can occur with excessive iron administration in pediatric patients 1, 2
• For IV iron dextran test dosing: use 10 mg for children <10 kg, 15 mg for children 10-20 kg, and 25 mg for children >20 kg 6
• Ensure personnel trained in emergency treatment are available when administering IV iron, with immediate access to epinephrine, diphenhydramine, and corticosteroids 6

Common Pitfalls to Avoid

The most significant practice variation occurs in total daily dosing, with surveys showing physicians prescribe anywhere from 2-6 mg/kg/day 7, 5. Stick to 2-3 mg/kg/day for standard treatment, reserving 6 mg/kg/day only for confirmed IDA requiring aggressive repletion 1, 3. Additionally, many providers order excessive diagnostic testing beyond CBC for straightforward nutritional IDA—only 15.6% appropriately recommend no additional tests when the diagnosis is clear 7.