From the Guidelines
Ferrous sulfate 65 mg should be prescribed every other day to improve tolerance and potentially enhance iron absorption, as supported by the most recent and highest quality study 1. When considering the management of iron deficiency anemia, the dosing frequency of iron supplements is crucial. The rationale behind prescribing ferrous sulfate 65 mg every other day is rooted in the body's response to iron intake. Daily iron supplementation can lead to increased levels of hepcidin, a hormone that regulates iron absorption, which can remain elevated for up to 48 hours after taking a dose 1. This increase in hepcidin can block further iron absorption, making daily dosing potentially less effective than alternate-day dosing.
Key considerations for iron supplementation include:
- Starting with ferrous iron salts (such as ferrous sulfate, ferrous fumarate, or ferrous gluconate) due to their cost-effectiveness and comparable efficacy to other formulations 1
- Being aware of common side effects, including constipation, diarrhea, and nausea, which can occur in a significant proportion of patients 1
- Understanding that taking iron with vitamin C (like orange juice) on an empty stomach may improve absorption, although evidence is mixed 1
- Avoiding consumption of tea, coffee, and calcium-containing foods around the time of iron supplementation, as these can inhibit iron absorption 1
The most recent guidance from the AGA clinical practice update on the management of iron deficiency anemia suggests that giving oral iron once a day at most is advisable, with every-other-day iron dosing potentially being better tolerated for some patients without compromising iron absorption rates 1. This approach aligns with the goal of minimizing side effects while effectively managing iron deficiency anemia, thus prioritizing patient morbidity, mortality, and quality of life.
From the Research
Dosage and Administration of Ferrous Sulfate
The dosage and administration of ferrous sulfate can vary depending on the individual's needs and the severity of their iron deficiency anemia.
- The standard dose of ferrous sulfate is 65 mg of elemental iron per day, but it can be taken every other day in some cases 2.
- A study published in The Lancet. Haematology found that taking iron supplements on alternate days and in single doses optimizes iron absorption and may be a preferable dosing regimen 2.
- Another study published in Cadernos de saude publica found that a weekly regimen of ferrous sulfate was no less effective than daily treatment in treating anemic childbearing-age women 3.
Rationale for Every Other Day Dosage
The rationale for taking ferrous sulfate every other day is to optimize iron absorption and minimize side effects.
- Iron absorption is regulated by the hormone hepcidin, which can be increased by daily iron supplementation, leading to decreased iron absorption from subsequent doses 2.
- Taking iron supplements on alternate days can help to avoid this negative feedback mechanism and improve iron absorption 2.
- Additionally, taking ferrous sulfate every other day may help to reduce gastrointestinal side effects, such as diarrhea and nausea, which are common with daily iron supplementation 4, 2.
Comparison with Other Iron Supplements
Ferrous sulfate is one of the most commonly prescribed iron supplements, but it can be compared with other forms of iron, such as ferrous glycinate chelate and iron polysaccharide complex.
- A study published in Nutrition found that ferrous sulfate was more effective than ferrous glycinate chelate in treating iron deficiency anemia in gastrectomized patients 5.
- Another study published in JAMA found that ferrous sulfate was more effective than iron polysaccharide complex in increasing hemoglobin concentration in young children with nutritional iron-deficiency anemia 4.