Adequate Ferrous Sulfate Dosing for Iron Deficiency Anemia
The recommended adequate dose of ferrous sulfate for treating iron deficiency anemia is 50-100 mg of elemental iron once daily, taken in the morning on an empty stomach, continued for 3 months after hemoglobin normalization. 1
Standard Dosing Recommendations
- Standard ferrous sulfate tablets contain 324mg of ferrous sulfate, which provides 65mg of elemental iron per tablet 2
- This single daily dose is sufficient for most adults with iron deficiency anemia
- Morning administration on an empty stomach maximizes absorption
- Treatment should continue for approximately 3 months after hemoglobin normalizes to adequately replenish iron stores 1
Dosing Considerations by Population
Iron requirements vary by population:
- Non-pregnant women and adolescent girls: 60-120 mg elemental iron daily
- School-age children: 60 mg elemental iron daily
- Adolescent boys: 120 mg elemental iron daily
- Pregnant women (preventive): 30 mg elemental iron daily
- Pregnant women (treatment of anemia): 60-120 mg elemental iron daily 1
Optimizing Absorption and Reducing Side Effects
- Take with 500 mg vitamin C (ascorbic acid) to enhance absorption 1
- Avoid taking with tea, coffee, calcium supplements, or high-fiber foods (wait at least 1 hour after iron intake) 1
- Consider alternate-day dosing which may improve absorption and reduce side effects 1
- Avoid multiple daily doses as this may not improve absorption due to hepcidin elevation 1
- Avoid modified-release preparations which have reduced absorption in the small intestine 1
Monitoring Response to Treatment
- Check hemoglobin response within the first 4 weeks of starting therapy 1
- Monitor hemoglobin and ferritin levels regularly until normalized
- Target ferritin >100 μg/L to ensure adequate iron stores are replenished 1
- Monitor blood count periodically (every 6 months initially) to detect recurrent iron deficiency anemia 1
Alternative Options
- For patients who cannot tolerate ferrous sulfate, consider:
- Consider intravenous iron when:
- Oral iron is contraindicated, ineffective, or not tolerated
- Rapid correction of anemia is required 1
Common Pitfalls to Avoid
- Discontinuing treatment too early (before 3 months after hemoglobin normalization)
- Prescribing multiple daily doses which may not improve absorption
- Using modified-release preparations which have reduced absorption
- Delaying intravenous iron therapy when clearly indicated 1
- Failing to investigate the underlying cause of iron deficiency while treating with iron supplements
Research has demonstrated that once-daily dosing of ferrous sulfate is as effective as multiple daily doses in treating iron deficiency anemia, with similar side effect profiles and potentially better adherence 3. In children, low-dose ferrous sulfate has been shown to be more effective than iron polysaccharide complex in increasing hemoglobin concentration 4.