What is the recommended dosing for oral ferrous sulphate (iron supplement) in patients with iron deficiency?

Recommended Dosing for Oral Ferrous Sulphate in Iron Deficiency

For adults with iron deficiency anemia, the recommended dose of oral ferrous sulphate is 50-100 mg of elemental iron once daily, which can be achieved with one tablet of ferrous sulphate 200 mg (containing 65 mg of elemental iron). 1, 2

Dosing Regimen

• Standard ferrous sulphate tablets contain 324 mg of ferrous sulfate, equivalent to 65 mg of elemental iron 3
• Treatment should be administered once daily in the morning on an empty stomach to maximize absorption 1, 4
• Recent evidence suggests that alternate day dosing may increase fractional iron absorption, as daily doses ≥60 mg stimulate hepcidin, which reduces subsequent iron absorption 4, 2
• For patients with moderate to severe anemia, commence oral iron therapy once daily with 50-100 mg elemental iron 2

Duration of Treatment

• Treatment should be continued for approximately 3 months after normalization of hemoglobin levels to ensure adequate repletion of iron stores 2, 1
• Monitor hemoglobin levels after 2-4 weeks of treatment to assess response 1, 5
• After successful treatment, blood counts should be monitored periodically (every 6 months initially) to detect recurrent iron deficiency anemia 2

Management of Side Effects

• If standard ferrous sulphate is not tolerated due to gastrointestinal side effects, consider:
  • Reducing the dose to one tablet every other day 2, 1
  • Switching to alternative oral iron preparations such as ferrous gluconate or ferrous fumarate 1, 2
  • Considering parenteral iron when oral iron is contraindicated, ineffective, or not tolerated 2

Special Considerations

• Modified-release preparations are generally less suitable for prescribing and more expensive 2, 1
• Taking iron with food reduces absorption by up to 50%, so patients should be advised to take supplements on an empty stomach 1, 5
• For patients with ongoing blood loss or malabsorption conditions, higher doses or parenteral iron may be necessary 5, 1
• Ferrous sulphate has been shown to be more effective than iron polysaccharide complex in increasing hemoglobin concentration in iron deficiency anemia 6

Common Pitfalls

• Failure to continue treatment after normalization of hemoglobin levels, which can lead to inadequate repletion of iron stores 2, 1
• Administering divided doses throughout the day, which may not improve absorption and can increase side effects 4, 2
• Not monitoring response to therapy, which is essential to confirm effectiveness and adjust treatment if necessary 1, 5
• Overlooking potential causes of treatment failure, such as ongoing blood loss, malabsorption, or concurrent deficiencies 5, 1