What is the recommended dosage and treatment plan for iron deficiency anemia using Ferrous (iron) sulfate solution 220 mg (44 mg FE)/5 mL?

Ferrous Sulfate Solution Dosing for Iron Deficiency Anemia

For ferrous sulfate solution 220 mg/5 mL (44 mg elemental iron per 5 mL), administer 5 mL once daily in the morning on an empty stomach to provide 44 mg elemental iron, which falls within the recommended 50-100 mg elemental iron daily range for optimal absorption and tolerability. 1, 2

Optimal Dosing Regimen

Standard Daily Dosing

• Give 5-10 mL (44-88 mg elemental iron) once daily in the morning as the preferred initial approach 1, 2
• Single daily dosing achieves similar hemoglobin response as multiple daily doses with significantly better tolerability 1, 2
• Doses above 60 mg elemental iron stimulate hepcidin elevation that persists 24 hours, reducing absorption of subsequent doses 1, 3
• Never split the dose throughout the day—this reduces total iron absorption by 35-45% due to hepcidin-mediated blockade 1, 2

Alternate-Day Dosing Option

• Consider 10-15 mL (88-132 mg elemental iron) every other day for patients with gastrointestinal intolerance 1, 2
• Alternate-day administration significantly increases fractional iron absorption compared to daily dosing 1, 3
• Reduces gastrointestinal adverse events by 44% (relative risk 0.56) 1, 2
• Produces similar hemoglobin increases after equivalent total iron dose, though slightly slower initial response 1

Administration Guidelines

Timing and Absorption Enhancement

• Administer in the morning on an empty stomach to avoid circadian hepcidin elevation that occurs with afternoon/evening dosing 2, 3
• Add vitamin C 250-500 mg with each dose to enhance absorption 1, 2
• Avoid taking with food, calcium, or proton pump inhibitors which impair absorption 2

Treatment Duration and Monitoring

Response Assessment

• Check hemoglobin at 2 weeks—failure to increase by at least 10 g/L predicts treatment failure with 90% sensitivity 1
• Recheck hemoglobin at 4 weeks to confirm adequate response (minimum 20 g/L increase expected) 1, 2
• Continue monitoring every 4 weeks until hemoglobin normalizes 2

Duration of Therapy

• Continue treatment for 3 months after hemoglobin normalization to replenish iron stores 1, 2
• Monitor blood counts every 6 months for the first year after treatment completion to detect recurrence 1, 2

When to Switch to Parenteral Iron

Clear Indications for IV Iron

• No hemoglobin response after 4 weeks of adequate oral therapy 1, 2
• Hemoglobin <100 g/L (10 g/dL) at presentation 1
• Gastrointestinal intolerance to oral iron 1
• Active inflammatory bowel disease 1, 2
• Malabsorption conditions (celiac disease, post-bariatric surgery) 1, 4
• Ongoing blood loss exceeding replacement capacity 2

Special Population Considerations

Inflammatory Bowel Disease

• Limit to 100 mg elemental iron daily (approximately 11 mL of this solution) and use only in clinically inactive disease with mild anemia 1, 2
• Switch to IV iron as first-line if disease is active or hemoglobin <100 g/L 1, 2

Pregnancy

• Consider IV iron during second and third trimesters for faster repletion 4

Critical Pitfalls to Avoid

Common Prescribing Errors

• Do not prescribe multiple daily doses—this is the most common error that reduces efficacy and increases side effects 1, 2
• Do not switch between different ferrous salts (sulfate, fumarate, gluconate) for intolerance—they have equivalent side effect profiles 1, 2
• Instead, try alternate-day dosing, ferric maltol, or parenteral iron for intolerance 1, 2
• Do not stop treatment when hemoglobin normalizes—continue for 3 additional months 1, 2

Monitoring Failures

• Do not wait longer than 4 weeks to assess response—early identification of non-responders prevents prolonged ineffective therapy 1, 2
• Do not assume treatment success without checking ferritin—hemoglobin may normalize while stores remain depleted 1, 2