Treatment of Anemia
The gold standard treatment for iron deficiency anemia is oral iron supplementation with 50-100 mg of elemental iron once daily, taken in the fasting state, with continuation for 3 months after hemoglobin normalization to replenish iron stores. 1
Diagnosis and Assessment
Before initiating treatment, proper diagnosis of the type of anemia is essential:
Iron studies: Check serum ferritin and transferrin saturation
- Ferritin <30 μg/L indicates definitive iron deficiency
- Ferritin 30-100 μg/L with transferrin saturation <20% suggests possible iron deficiency, especially with inflammation 1
Vitamin deficiency screening: Check serum folate and vitamin B12 levels, particularly in patients with normal iron studies 2
- Vitamin B12 deficiency occurs in approximately 3.9% of anemic cancer patients 2
Treatment Algorithm for Anemia
1. Iron Deficiency Anemia
Oral Iron Therapy (First-Line)
- Dosage: 50-100 mg elemental iron once daily 1
- Timing: Take on empty stomach to maximize absorption
- Duration: Continue for 3 months after hemoglobin normalization
- Expected response: Increase in hemoglobin of ≥1 g/dL within 4 weeks 1
- Monitoring: Check hemoglobin after 2-4 weeks of treatment
Intravenous Iron Therapy (Consider when):
- Oral iron is not tolerated
- No hemoglobin increase of at least 10 g/L after 2 weeks of oral therapy
- Malabsorption conditions
- Chronic inflammatory conditions
- Ongoing blood loss exceeding oral replacement capacity 1
IV Iron Options:
- Ferric carboxymaltose: 1,000 mg IV over 10-15 minutes 2, 3
- Iron sucrose: 200 mg IV over 5 minutes weekly × 5 doses 2
- Sodium ferric gluconate: 125 mg IV over 60 minutes weekly × 8 doses 2
2. Vitamin B12 Deficiency Anemia
- Initial treatment: 100 mcg vitamin B12 daily for 6-7 days by intramuscular injection
- Maintenance: If clinical improvement and reticulocyte response observed, give same amount on alternate days for seven doses, then every 3-4 days for 2-3 weeks
- Long-term: 100 mcg monthly for life 4
- Important: Avoid intravenous route as most of the vitamin will be lost in urine 4
3. Iron-Refractory Iron Deficiency Anemia (IRIDA)
For patients with unexplained microcytic anemia with low transferrin saturation and normal/reduced serum ferritin who don't respond to oral iron:
- Initial approach: Trial of oral iron combined with ascorbic acid
- If inadequate response: Switch to intravenous iron supplementation
- Monitoring: Keep serum ferritin levels below 500 μg/L to avoid iron overload toxicity 2
Special Considerations
Cancer-Related Anemia
- Assess iron studies in all cancer patients with hemoglobin <10 g/dL
- Consider IV iron with or without erythropoiesis-stimulating agents (ESAs) 2
- Target both absolute iron deficiency (TSAT <20%, ferritin <30 ng/mL) and functional iron deficiency (TSAT 20-50%, ferritin 30-800 ng/mL) 2
Chronic Kidney Disease
- IV iron therapy is often more effective than oral supplementation 5
- Monitor for potential adverse effects of parenteral iron therapy
Common Pitfalls to Avoid
- Inadequate monitoring: Failure to check hemoglobin response after 2 weeks may delay recognition of treatment failure 1
- Premature discontinuation: Stopping iron supplementation once hemoglobin normalizes without continuing for 3 months to replenish iron stores 1
- Overuse of blood transfusion: Transfusion should be reserved for severe symptomatic anemia 1
- Ignoring non-response: Failure to investigate causes of non-response to iron therapy 1
- Inappropriate dosing: Recent evidence suggests lower doses of iron (19 mg) may be as effective as higher doses (38 mg) for maintaining iron stores in certain populations 6
Remember that identifying and treating the underlying cause of anemia is essential for long-term management and prevention of recurrence.