Ferrous sulfate dosage in anemia
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Ferrous Sulfate Dosage in Anemia: Efficacy and Dosing Schedules
Standard Dosage and Effectiveness in Children and Adults
Ferrous sulfate is widely used to treat iron-deficiency anemia, with typical dosages ranging from 40 mg to 200 mg of elemental iron per day, depending on age and severity. In children, a daily dose of 3 mg/kg elemental iron has been shown to significantly increase hemoglobin and ferritin levels over 12 weeks, with once-daily dosing proving effective and well-tolerated 15. In adults, especially non-pregnant women with mild to moderate anemia, 200 mg of ferrous sulfate twice daily led to normalization of hemoglobin in 79% of participants after 12 weeks, demonstrating strong efficacy and good tolerance .
Once-Daily vs. Multiple-Daily Dosing
Research comparing once-daily to multiple-daily dosing regimens in infants and pregnant women found that a single daily dose is as effective as two or three divided doses in improving hemoglobin and ferritin levels 16. Once-daily dosing also results in fewer side effects, which can improve adherence to treatment, especially in populations where compliance is a challenge 16. In pregnancy, both once-daily (65 mg) and twice-daily (130 mg) regimens were equally effective in preventing anemia, but the once-daily group experienced fewer side effects .
Daily vs. Weekly Supplementation
Daily supplementation of ferrous sulfate is more effective than weekly dosing in improving hemoglobin levels in children under five, although neither regimen significantly reduced the overall prevalence of anemia. Adding other micronutrients to iron supplementation did not provide additional benefits over iron alone . In adolescents, once-weekly low-dose supplementation (150 mg) for 16 weeks effectively improved iron status and eliminated iron deficiency anemia, suggesting that lower-frequency dosing may be suitable for prevention in certain populations .
Comparison with Other Iron Formulations
Ferrous sulfate remains the most effective and commonly prescribed oral iron for moderate to severe anemia, outperforming iron polysaccharide complexes in increasing hemoglobin and ferritin levels in children 58. In cancer patients and pregnant women, ferrous sulfate at conventional doses (50–105 mg/day) is as effective as other iron formulations, such as ferrous bisglycinate, though the latter may have fewer gastrointestinal side effects 49. In postpartum women, oral ferrous sulfate (160 mg/day) was less effective than intravenous iron in improving laboratory parameters, but all regimens had similar effects on fatigue .
Conclusion
Ferrous sulfate is a highly effective and well-tolerated treatment for iron-deficiency anemia across age groups. Once-daily dosing of 40–200 mg elemental iron is generally as effective as multiple daily doses, with fewer side effects and better adherence. Daily supplementation is more effective than weekly dosing for improving hemoglobin, though weekly regimens may be considered for prevention in specific populations. Ferrous sulfate remains the standard oral iron therapy, with alternative formulations offering similar efficacy but sometimes improved tolerability.
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