Is 325mg of ferrous sulfate (containing 65mg of elemental iron) the correct dose for treating iron deficiency anemia in adults?

Ferrous Sulfate 325/65 mg for Iron Deficiency Anemia

Yes, 325 mg of ferrous sulfate (containing 65 mg of elemental iron) is the correct standard dose for treating iron deficiency anemia in adults. 1

Dosing Recommendations

• The FDA-approved formulation contains 324 mg of ferrous sulfate, equivalent to 65 mg of elemental iron 1
• The British Society of Gastroenterology (BSG) recommends 50-100 mg of elemental iron daily for treating iron deficiency anemia 2
• The American Gastroenterological Association recommends ferrous sulfate 200 mg (65 mg elemental iron) once daily as first-line treatment 3

Administration Guidelines

• Once-daily dosing is recommended rather than multiple daily doses 2, 3
• Take on an empty stomach for optimal absorption (without food or other medications) 2
• Morning administration may be preferable for compliance 3
• Alternate-day dosing may be considered for patients with gastrointestinal side effects, as it can provide similar efficacy with fewer side effects 2, 4

Monitoring Response

• Check hemoglobin after 2 weeks of treatment to assess response 2, 3
• An increase in hemoglobin of at least 10 g/L after 2 weeks strongly predicts successful treatment (sensitivity 90.1%, specificity 79.3%) 2
• If no response is observed after 2 weeks, consider alternative approaches (different formulation, alternate-day dosing, or parenteral iron) 2

Duration of Treatment

• Continue treatment for approximately 3 months after normalization of hemoglobin to ensure adequate repletion of iron stores 2, 3, 5
• Monitor blood counts periodically (perhaps every 6 months initially) after treatment to detect recurrent iron deficiency anemia 2

Alternative Options

• For patients with gastrointestinal intolerance:
  • Consider alternate-day dosing 2, 4
  • Try ferric maltol if available 2
  • Consider parenteral iron for those who cannot tolerate oral iron 2, 3

Common Pitfalls to Avoid

1. Inadequate duration of treatment: Stopping treatment once hemoglobin normalizes without continuing for the additional 3 months needed to replenish iron stores 2, 3

2. Improper administration: Taking with food reduces absorption by up to 50% 2

3. Switching between different iron salts: This practice is not supported by evidence when side effects occur 3

4. Failure to monitor response: Not checking hemoglobin after 2 weeks may delay recognition of treatment failure 3

5. Excessive dosing: Higher doses don't improve absorption and may increase side effects 2, 4

In conclusion, ferrous sulfate 325 mg (providing 65 mg of elemental iron) once daily is the correct standard dose for treating iron deficiency anemia in adults, with strong evidence supporting this dosing regimen for optimal efficacy and tolerability.