What is the recommended treatment for iron deficiency anemia according to Singapore guidelines?

Treatment of Iron Deficiency Anemia According to Singapore Guidelines

For iron deficiency anemia in Singapore, oral iron should be considered as first-line treatment in patients with mild anemia and clinically inactive disease, while intravenous iron should be used as first-line therapy in patients with clinically active disease, previous intolerance to oral iron, hemoglobin below 100 g/L, or those requiring erythropoiesis-stimulating agents. 1

First-Line Treatment Options

Oral Iron Therapy

• Recommended for patients with mild anemia and clinically inactive disease 1
• Most commonly prescribed as ferrous sulfate 200 mg twice daily 1
• Should be continued for 3 months after iron deficiency correction to replenish stores 1
• Alternative formulations for better tolerance:
  • Ferrous fumarate
  • Ferrous gluconate
  • Iron suspensions
• Consider adding ascorbic acid (250-500 mg twice daily) to enhance absorption 1

Intravenous Iron Therapy

• First-line treatment recommended for: 1, 2

  • Patients with clinically active disease
  • Previous intolerance to oral iron
  • Hemoglobin below 100 g/L
  • Patients requiring erythropoiesis-stimulating agents

• Available IV iron preparations in Singapore: 1, 2

  1. Ferric carboxymaltose (Ferinject/Injectafer)

     • Maximum single dose: 1000 mg
     • Administration time: 15 minutes
     • No test dose required

  2. Iron sucrose (Venofer)

     • Maximum single dose: 200 mg
     • Administration time: 10 minutes
     • No test dose required

  3. Iron dextran (Cosmofer)

     • Maximum single dose: 20 mg/kg
     • Administration time: 6 hours
     • Can be given IV or IM
     • Test dose required due to risk of anaphylaxis

Dosing and Administration Guidelines

For Ferric Carboxymaltose (Preferred Option)

• For patients ≥50 kg: 750 mg IV in two doses separated by at least 7 days (total 1,500 mg) 3
• Alternative dosing: 15 mg/kg up to maximum 1,000 mg as single dose 3
• For patients <50 kg: 15 mg/kg in two doses separated by at least 7 days 3
• Dilute up to 1,000 mg in no more than 250 mL of sterile 0.9% sodium chloride 2, 3
• Administer over at least 15 minutes 2, 3

For Iron Sucrose

• Typical dose: 200 mg per infusion 1, 4
• Can be administered as bolus over 10 minutes 1
• Multiple infusions needed to reach total iron deficit 4

Monitoring and Follow-up

• Hemoglobin should rise by approximately 2 g/dL after 3-4 weeks of treatment 1

• Iron status should be re-evaluated 3 months after administration 2

• Target parameters: 2

  • Hemoglobin >12 g/dL
  • Ferritin >100 μg/L

• Failure to respond may be due to: 1

  • Poor compliance (with oral therapy)
  • Misdiagnosis
  • Continued blood loss
  • Malabsorption

• After successful treatment with IV iron, re-treatment should be initiated when: 1

  • Serum ferritin drops below 100 mg/L
  • Hemoglobin falls below 12 g/dL (females) or 13 g/dL (males)

Special Considerations

• Monitor serum phosphate levels in patients receiving ferric carboxymaltose, especially those requiring repeat courses 2, 5
• Hypophosphatemia is a common side effect (50-74%) with ferric carboxymaltose 5
• For patients with inflammatory bowel disease, IV iron is more effective, shows faster response, and is better tolerated than oral iron 1
• Avoid extravasation during IV administration as it may cause long-lasting brown discoloration 3

Adverse Effects to Monitor

• Common adverse effects of IV iron: 6, 7

  • Headache
  • Dizziness
  • Nausea
  • Abdominal pain
  • Injection site reactions
  • Rash

• Risk of severe infusion reactions is <1% with modern preparations 5

• Ferric carboxymaltose has lower risk of anaphylactic reactions compared to iron dextran 7

By following these guidelines, clinicians in Singapore can effectively manage iron deficiency anemia while minimizing adverse effects and optimizing patient outcomes.