Iron Dosage for Anemia Treatment
For adults with iron deficiency anemia, the recommended daily dose is 50-100 mg of elemental iron once daily, which typically corresponds to one 325 mg tablet of ferrous sulfate. 1
Types of Oral Iron Preparations and Elemental Iron Content
Different iron salt preparations contain varying amounts of elemental iron per 325 mg tablet:
| Iron Preparation | Tablet Size (mg) | Elemental Iron (mg) |
|---|---|---|
| Ferrous sulfate | 325 | 65 |
| Ferrous fumarate | 325 | 108 |
| Ferrous gluconate | 325 | 35 |
| Polysaccharide-iron complex | - | 150 |
Dosing Recommendations by Patient Population
General Adult Population
- Initial therapy: 50-100 mg elemental iron once daily 1
- Duration: Continue for approximately 3 months after normalization of hemoglobin levels to ensure adequate repletion of iron stores 1
Patients with Chronic Kidney Disease
- Recommended dose: 200 mg elemental iron daily, divided into 2-3 doses 2, 1
- Pediatric patients: 2-3 mg/kg/day of elemental iron in divided doses 2
Optimizing Iron Absorption
- Take iron on an empty stomach, without food or other medications 2, 1
- Food can reduce iron absorption by up to 50% if eaten within 2 hours before or 1 hour after an iron supplement 2
- Avoid taking with calcium-containing foods/supplements or aluminum-based phosphate binders 2, 1
- Morning dosing may be more effective than afternoon/evening dosing due to circadian variations in hepcidin levels 3
Managing Side Effects
For patients experiencing gastrointestinal side effects:
- Consider lower doses (35-65 mg elemental iron daily)
- Try alternate-day dosing schedule (60-120 mg every other day) 3
- Switch to a different iron formulation 1
- Take the supplement at bedtime 2
Monitoring Treatment Response
- Assess response after 1 month of therapy
- Look for hemoglobin rise of ≥1.0 g/dL and normalization of iron parameters 1
- If response is inadequate:
- Increase daily dose or switch to twice-daily dosing
- Try an alternate oral iron preparation
- Consider intravenous iron 1
Common Pitfalls to Avoid
- Inadequate dosing: Ensure sufficient elemental iron is provided
- Insufficient duration: Continue treatment for 3 months after hemoglobin normalization
- Poor absorption: Address factors affecting absorption (timing with meals, medications)
- Ignoring side effects: Side effects reduce compliance; adjust regimen if needed
- Inappropriate monitoring: Follow hemoglobin and iron parameters to ensure adequate response
Recent research suggests that alternate-day dosing with 60-120 mg elemental iron may maximize absorption while reducing side effects compared to daily divided doses 3, but the standard recommendation remains 50-100 mg daily for most patients 1.