What is the best-tolerated oral iron supplement?

Best Tolerated Oral Iron Supplement

Ferric maltol is the best-tolerated oral iron supplement, with GI side effects and treatment cessation rates comparable to placebo, making it an excellent choice for patients with previous intolerance to traditional iron salts. 1

Comparison of Oral Iron Formulations

Traditional Iron Salts

• Ferrous Sulfate: Most commonly prescribed due to simplicity, low cost, and established efficacy 2

  • Contains 65mg elemental iron per 200mg tablet 1, 3
  • Highest incidence of adverse effects (32.3% overall, 30.2% gastrointestinal) 2
  • Most cost-effective option at approximately £1.00 for 28 days of treatment 1

• Ferrous Gluconate: Contains less elemental iron (37mg per 300mg tablet) 1, 4

  • May be better tolerated than ferrous sulfate but still causes significant GI side effects
  • Higher cost (£2.18 for 28 days) compared to ferrous sulfate 1

• Ferrous Fumarate: Contains high elemental iron content (69-106mg per tablet) 1

  • Similar side effect profile to ferrous sulfate
  • Cost comparable to ferrous sulfate (£1.00-1.40 for 28 days) 1

Newer Formulations

• Ferric Maltol: Superior tolerability profile 1

  • GI side effects comparable to placebo
  • Treatment cessation rates similar to placebo
  • Normalizes hemoglobin in 63-66% of cases after 12 weeks
  • Long-term tolerance maintained during a year of treatment with 89% achieving normal hemoglobin 1
  • Higher cost (£47.60 for 28 days) but less expensive than parenteral iron 1

• Iron with Mucoproteose: Lowest incidence of adverse effects (4.1% overall, 3.7% gastrointestinal) 2

• Iron Protein Succinylate: Relatively low adverse effects (7.3% overall, 7% gastrointestinal) 2

Strategies to Improve Tolerability

1. Optimal Dosing:

   • Once-daily dosing (50-100mg elemental iron) is as effective as twice-daily dosing 1
   • Alternate-day dosing may increase fractional iron absorption 1

2. Administration Timing:

   • Take on an empty stomach in the morning to maximize absorption 2
   • Avoid coffee, tea, and food within 2 hours of taking iron (can reduce absorption by up to 54%) 2

3. Enhancing Absorption:

   • Take with 500mg vitamin C (ascorbic acid) to enhance absorption 2
   • Avoid enteric-coated formulations as they decrease absorption despite improved tolerability 2

4. Duration of Treatment:

   • Continue for 3 months after normalizing hemoglobin to ensure adequate repletion of iron stores 1, 2
   • Monitor hemoglobin response within first 4 weeks 1

Special Considerations

• Treatment Failure: If no improvement is seen after 1 month, further evaluation is necessary 2
• Alternative Options: Consider parenteral iron when oral iron is contraindicated, ineffective, or not tolerated 1
• Monitoring: After restoration of hemoglobin and iron stores, monitor blood count periodically (perhaps every 6 months initially) to detect recurrent iron deficiency anemia 1

Common Pitfalls

1. Overemphasis on Cost: While ferrous sulfate is cheapest, its high side effect profile (up to 32.3%) leads to poor compliance and treatment failure 2

2. Ignoring Dropout Rates: Up to 40% of patients discontinue oral iron due to side effects 2, making tolerability a critical factor in successful treatment

3. Inadequate Duration: Failing to continue treatment for 3 months after hemoglobin normalization results in inadequate iron store repletion 1, 2

4. Missing Absorption Factors: Not accounting for factors that inhibit absorption (food, tea, coffee) or enhance it (vitamin C) 2