From the Guidelines
Extended release ferrous sulfate is preferred for iron supplementation due to its improved tolerability and reduced gastrointestinal side effects, leading to better patient compliance and overall treatment outcomes for conditions like iron deficiency anemia. The standard dose is typically 325 mg once or twice daily, providing 105 mg of elemental iron per tablet, as seen in the comparison of oral iron preparations available in the UK 1. This formulation gradually releases iron throughout the digestive tract, reducing the concentration at any one point and minimizing common side effects like nausea, abdominal pain, constipation, and diarrhea that often lead to poor adherence with immediate-release formulations.
- Key points to consider when prescribing extended release ferrous sulfate include:
- Taking iron supplements on an empty stomach with water or orange juice (vitamin C enhances absorption)
- Avoiding milk, antacids, calcium supplements, coffee, or tea within two hours of taking iron, as these can reduce absorption
- Monitoring patient response and adjusting treatment as necessary, with regular Hb monitoring recommended every 4 weeks until the Hb is in the normal range 1 However, a more recent study published in 2024 found that no single formulation of oral iron has any advantages over any other, and ferrous sulfate is preferred as the least expensive iron formulation 1. This suggests that the choice of iron formulation should be based on cost and patient tolerance, rather than any perceived advantages of one formulation over another.
- Factors to consider when choosing an iron formulation include:
- Cost: ferrous sulfate is the least expensive option 1
- Patient tolerance: extended release formulations may be better tolerated by some patients due to reduced gastrointestinal side effects
- Treatment outcomes: regular Hb monitoring and adjustment of treatment as necessary can help ensure optimal outcomes for patients with iron deficiency anemia 1
From the Research
Reasons for Preference of Extended Release Ferrous Sulfate
- The extended-release formulation of ferrous sulfate has been shown to have a lower incidence of gastrointestinal adverse effects compared to other ferrous and ferric salts 2.
- A study comparing the efficacy and tolerability of a prolonged release ferrous sulphate formulation (V0355) with a referential ferrous sulphate (Ferrograd®) found that V0355 was as efficient as Ferrograd® in treating anaemia and exhibited a better gastrointestinal tolerance profile 3.
- The absorption of iron from slow-release tablets has been found to be significantly higher compared to rapidly-disintegrating tablets in normal subjects, blood donors, and patients with iron deficiency anaemia 4.
- Extended-release ferrous sulfate with mucoproteose has been reported to have the lowest incidence of adverse effects (4.1% for overall adverse effects, 3.7% for gastrointestinal adverse effects) compared to other oral iron supplements 5.
Key Benefits
- Reduced gastrointestinal side effects, such as nausea, constipation, and heartburn, which can improve treatment compliance.
- Improved absorption of iron, leading to more effective treatment of iron deficiency anaemia.
- Better tolerability profile compared to other oral iron supplements, making it a preferred choice for patients with iron deficiency anaemia.
Comparison with Other Treatments
- Oral iron supplements, including extended-release ferrous sulfate, have been compared to intravenous iron therapy, with the latter showing faster increases in hemoglobin and serum ferritin levels 6.
- However, extended-release ferrous sulfate remains a preferred choice due to its better tolerability profile and reduced risk of adverse effects compared to other oral iron supplements 5.