What is the recommended dosage and administration of liquid iron supplements for individuals with iron deficiency?

Liquid Iron Supplement Dosing and Administration

For iron deficiency anemia, administer 50-100 mg of elemental iron once daily or 100-200 mg on alternate days, taken in the morning on an empty stomach, using liquid ferrous sulfate or ferrous gluconate preparations. 1, 2

Recommended Liquid Formulations

• Ferrous sulfate liquid (125 mg/mL) provides 25 mg elemental iron per mL and is the gold standard oral iron preparation due to known elemental iron content and low cost 3, 2
• Sodium feredate liquid (190 mg/5 mL) provides 27.5 mg elemental iron per 5 mL as an alternative formulation 3
• Ferrous fumarate liquid (140 mg/5 mL) provides 45 mg elemental iron per 5 mL 3

Optimal Dosing Strategy

Alternate-day dosing maximizes iron absorption while minimizing gastrointestinal side effects compared to daily dosing 1, 4:

• For iron deficiency without anemia: 50-100 mg elemental iron once daily OR 100-200 mg on alternate days 1
• For iron deficiency anemia: 100-200 mg elemental iron on alternate days achieves superior fractional absorption compared to daily dosing 1, 4
• Single morning doses are superior to divided doses throughout the day, as afternoon/evening dosing after a morning dose reduces absorption due to hepcidin elevation 4

Pediatric Dosing

• Standard pediatric dose: 2-3 mg/kg/day of elemental iron in divided doses 3
• Liquid preparations are more appropriate for young children than solid formulations 3

Administration Guidelines

Timing and absorption optimization:

• Take iron in the morning on an empty stomach (at least 2 hours before or 1 hour after food) to maximize absorption 3, 1
• Food reduces iron absorption by up to 50% 3
• Add 80-250 mg vitamin C (ascorbic acid) with each dose to enhance absorption, though clinical benefit evidence is limited 1, 2
• Avoid tea or coffee within 1 hour after taking iron as they inhibit absorption 2
• Aluminum-based phosphate binders also reduce iron absorption 3

Managing Tolerability Issues

If gastrointestinal side effects occur (constipation, diarrhea, nausea are common) 3:

• Start with lower doses (50 mg elemental iron) and increase gradually 3
• Switch to alternate-day dosing, which reduces GI adverse events by 44% (relative risk 0.56) 1
• Take the supplement at bedtime 3
• Consider switching between ferrous sulfate, gluconate, or fumarate preparations 3

Monitoring Response

Assess treatment effectiveness systematically 3, 1, 2:

• Check hemoglobin at 4 weeks: failure to achieve at least 10 g/L rise after 2 weeks predicts treatment failure 1
• Hemoglobin should increase by 1 g/dL within 2 weeks in anemic patients 1, 2
• Ferritin should increase within 1 month in adherent patients 2
• Continue treatment for 3 months after hemoglobin normalization to replenish iron stores 3, 2

When to Switch to Intravenous Iron

Consider parenteral iron as first-line treatment in specific situations 3, 1:

• Active inflammatory bowel disease with hemoglobin <100 g/L 3
• Previous intolerance to oral iron 3, 1
• No hemoglobin response after 4 weeks of adequate oral therapy 1
• Ongoing blood loss exceeding oral iron absorption capacity 2
• Impaired gastrointestinal absorption (celiac disease, post-bariatric surgery) 5
• Chronic kidney disease or heart failure requiring erythropoiesis-stimulating agents 3

Critical Contraindications

Do not supplement iron when 3:

• Ferritin levels are normal or elevated, as this is potentially harmful 3
• Active infection is present without treating the underlying cause first 3

Special Population Considerations

• Pregnant women (second/third trimester): 60-120 mg elemental iron daily, though intravenous iron is preferred for rapid correction 2, 5
• Inflammatory bowel disease with inactive disease: Limit to maximum 100 mg elemental iron daily; use only in mild anemia 1
• Chronic kidney disease on erythropoietin: Often require intravenous iron due to increased iron demands 3