From the Guidelines
The recommended dose and frequency of ferrous sulfate for adults with iron deficiency anemia is 50-100 mg of elemental iron per day, taken orally once daily, as it provides the best compromise between efficacy and gastrointestinal tolerability 1.
Key Considerations
- The optimal dosage and frequency may vary depending on individual patient factors, such as the severity of iron deficiency anemia and the presence of gastrointestinal side effects.
- Ferrous sulfate can be taken on an empty stomach to maximize absorption, but if gastrointestinal side effects occur, it can be taken with food, although this may reduce absorption by 40-50% 1.
- Vitamin C-containing foods or supplements can enhance iron absorption, and patients should be aware that ferrous sulfate may cause dark or black stools, which is a normal and harmless side effect.
Treatment Duration and Monitoring
- Treatment duration typically ranges from 3-6 months to replenish iron stores completely, even after hemoglobin levels normalize 1.
- Regular hemoglobin monitoring is recommended to ensure an ultimately satisfactory response, with the optimal interval being every 4 weeks until the hemoglobin is in the normal range 1.
Alternative Options
- For patients with significant intolerance to oral iron therapy, alternative options such as oral ferric maltol, alternate day oral iron, or parenteral iron may be considered 1.
- The standard practice of switching to a different traditional iron salt is not supported by evidence, and parenteral iron may be more effective in patients with chronic disease, continuing blood loss, impaired absorption, or gastrointestinal inflammatory pathology 1.
From the Research
Recommended Dose and Frequency of Ferrous Sulfate
- The recommended dose of ferrous sulfate varies depending on the study, but common doses include:
- The frequency of ferrous sulfate also varies, with some studies using:
- It's worth noting that the efficacy of ferrous sulfate can be similar regardless of the frequency, with one study showing that a single-dose daily regimen was as effective as a 3-times-daily regimen 3
- Additionally, some studies suggest that lower therapeutic doses of iron may be sufficient for the management of iron deficiency anemia, with doses between 80 mg and 200 mg of elemental iron per day being effective 5
Comparison to Other Iron Supplements
- Ferrous sulfate has been compared to other iron supplements, such as iron protein succinylate, and has been shown to be equally effective in treating iron deficiency anemia 5
- However, ferrous sulfate may cause more gastrointestinal side effects than other supplements, such as iron protein succinylate 5
- Intravenous iron supplements, such as ferric carboxymaltose, may be more effective than oral ferrous sulfate in correcting iron deficiency anemia, especially in cases of heavy uterine bleeding 4