Ferrous Sulfate Dosing for Anemia Treatment
For iron deficiency anemia, the recommended dose of ferrous sulfate is 1000 mg daily (providing 65 mg elemental iron per 325 mg tablet), taken as a single daily dose or divided throughout the day. 1
Dosing Recommendations by Patient Population
- Standard adult dosing: 1000 mg ferrous sulfate daily (providing approximately 200 mg elemental iron) 1
- Pregnant women: 200-300 mg ferrous sulfate daily (providing 60-100 mg elemental iron) 2
- Women with heavy menstrual bleeding: Higher doses of ferrous sulfate providing 50-100 mg elemental iron daily may be required 2
- Patients with inflammatory bowel disease or chronic kidney disease: Should not exceed 100 mg elemental iron per day 2
- Children with nutritional iron deficiency anemia: 3 mg/kg of elemental iron once daily as ferrous sulfate drops 3
Administration Guidelines for Optimal Absorption
- Timing: Take on an empty stomach, 1 hour before or 2 hours after meals to maximize absorption 2
- Enhancing absorption: Take with vitamin C (ascorbic acid) or citrus juice to improve iron absorption 2
- Avoid interactions: Do not take with calcium supplements, dairy products, tea, coffee, or antacids as they reduce absorption 2
- Alternative schedule: Consider alternate-day dosing (e.g., 60-120 mg elemental iron every other day) which may improve absorption and reduce side effects 4
Duration of Treatment
- Continue treatment for 3 months after hemoglobin normalizes to adequately replenish iron stores 1, 2
- Monitor response: Expect hemoglobin to rise by approximately 2 g/dL after 3-4 weeks of therapy 1
- Follow-up monitoring: Check hemoglobin and red cell indices at 3-month intervals for one year after correction, then annually 1
Managing Side Effects
- Common side effects: Gastrointestinal issues including nausea, constipation, abdominal discomfort, and dark stools 2
- If side effects occur: Consider taking with food, although this may reduce absorption by 40-50% 2
- Alternative formulations: If ferrous sulfate is not tolerated, consider ferrous gluconate (38 mg elemental iron per 325 mg tablet) or ferrous fumarate (106 mg elemental iron per 325 mg tablet) 1, 2
- Dose adjustment: Lower doses may be better tolerated while still being effective 5, 4
When to Consider Intravenous Iron
- Poor oral tolerance: If gastrointestinal side effects persist despite modifications 1, 2
- Malabsorption: In patients with conditions affecting iron absorption 1, 2
- No response to oral therapy: If no improvement in hemoglobin after 4 weeks of compliant oral therapy 2
- Severe anemia: In cases requiring rapid correction of iron deficiency 1, 2
Special Considerations
- Single daily dosing: May be as effective as multiple daily doses and could improve adherence 6
- Morning dosing: Taking iron in the morning may be more effective due to circadian variations in hepcidin levels 4
- Caution during infections: Consider withholding iron supplementation during active infections 1