Iron Supplementation for Low Hemoglobin
For patients with low hemoglobin due to iron deficiency, intravenous iron should be considered first-line treatment for those with clinically active inflammatory disease, previous intolerance to oral iron, hemoglobin below 100 g/L, or those requiring erythropoiesis-stimulating agents, while oral iron supplementation should be used for patients with mild anemia and clinically inactive disease. 1
Diagnosis of Iron Deficiency Anemia
Before initiating treatment, confirm iron deficiency with:
- Complete blood count
- Serum ferritin
- C-reactive protein (CRP)
Diagnostic criteria:
- Without inflammation: serum ferritin <30 μg/L
- With inflammation: serum ferritin up to 100 μg/L may still indicate iron deficiency 1
Oral Iron Therapy
When to use oral iron:
- Mild anemia (Hb >10 g/dL)
- Clinically inactive disease
- No previous intolerance to oral iron 1
Recommended oral preparations:
Ferrous sulfate: 200 mg tablet (65 mg elemental iron) once daily 1, 2
- Most cost-effective option at approximately £1.00 for 28 days
- Standard first-line therapy
Ferrous gluconate: 324 mg tablet (38 mg elemental iron) once daily 3
- Alternative for patients who cannot tolerate ferrous sulfate
Ferric maltol: 30 mg twice daily
- Better tolerated in patients with inflammatory bowel disease
- More expensive option (£47.60 for 28 days) 1
Dosing considerations:
- No more than 100 mg elemental iron per day is recommended 1
- Once-daily dosing may be as effective as multiple daily doses with fewer side effects 4
- Alternate-day dosing may improve fractional iron absorption 1
Intravenous Iron Therapy
When to use IV iron:
- Hemoglobin <100 g/L (severe anemia)
- Clinically active inflammatory disease
- Previous intolerance to oral iron
- Failure to respond to oral iron (Hb increase <1.0 g/dL after 14 days) 1, 5
- Malabsorption conditions
IV iron formulations:
- Iron sucrose: single doses up to 7 mg/kg, typically limited to 200-300 mg per treatment
- Ferric carboxymaltose: 500-1000 mg (up to 20 mg/kg) delivered within 15 minutes 1
Dosing guidelines by hemoglobin level:
| Hemoglobin g/dL | Body weight <70 kg | Body weight ≥70 kg |
|---|---|---|
| 10-12 (women) | 1000 mg | 1500 mg |
| 10-13 (men) | 1000 mg | 1500 mg |
| 7-10 | 1500 mg | 2000 mg |
Monitoring Response
- Check hemoglobin and iron indices after 3-4 weeks of treatment 4
- Expected response: increase in hemoglobin of approximately 2 g/dL after 3-4 weeks 4
- Target hemoglobin levels: >12 g/dL for women and >13 g/dL for men 4
- Target ferritin: >100 μg/L 4
Long-term monitoring:
- Monitor every 3 months for at least a year after correction
- Then every 6-12 months thereafter 1
- Consider retreatment when ferritin drops below 100 μg/L or hemoglobin falls below gender-specific targets 1
Important Considerations
- Blood transfusion should be reserved for patients with severe symptomatic anemia or circulatory compromise 1
- Recurrent anemia may indicate persistent intestinal disease activity even with normal inflammatory parameters 1
- Avoid iron overload by maintaining ferritin levels below 500-800 μg/L 1
- Poor response to oral iron after 14 days (Hb increase <1.0 g/dL) should prompt switch to IV iron 5
Pitfalls to Avoid
- Inadequate dosing or duration of treatment
- Overlooking compliance issues with oral preparations
- Failure to monitor and treat recurrent iron deficiency
- Excessive iron supplementation leading to iron overload
- Intramuscular iron is obsolete and should be avoided due to pain, tissue damage, and side effects 1
By following these evidence-based recommendations, you can effectively manage iron deficiency anemia while minimizing side effects and optimizing patient outcomes.