From the Guidelines
For iron deficiency in adults, the recommended initial treatment is a once daily dose of 50–100 mg of elemental iron, such as one ferrous sulfate 200 mg tablet a day, taken in the fasting state. This recommendation is based on the British Society of Gastroenterology guidelines for the management of iron deficiency anaemia in adults 1. The guidelines suggest that this dose may be the best compromise option for initial treatment, considering the balance between efficacy and tolerability.
The choice of oral iron preparation is also important, with ferrous sulfate, ferrous fumarate, and ferrous gluconate being common options. Ferrous sulfate 200 mg tablets are a cost-effective option, with an approximate cost of £2.50 for 28 days 1. It is essential to monitor the initial haematological response and modify the treatment regimen as needed in case of apparent therapeutic failure.
In patients who cannot tolerate oral iron or have malabsorption, parenteral iron is a viable alternative. Parenteral iron is more effective than continuing traditional oral therapy in patients with chronic disease, continuing blood loss, impaired absorption, or GI inflammatory pathology 1. The optimal duration of oral iron therapy to replenish iron stores is unclear, but it is traditionally recommended to continue treatment for 2-3 months after hemoglobin normalization.
Regular hemoglobin monitoring is recommended to ensure a satisfactory response, with a suggested interval of every 4 weeks until the hemoglobin is in the normal range 1. The absence of an Hb rise of at least 10 g/L after 2 weeks of daily oral iron replacement therapy is strongly predictive of subsequent failure to achieve a sustained haematological response 1.
In summary, the key points for the dosing of iron for iron deficiency in adults are:
- Initial treatment with a once daily dose of 50–100 mg of elemental iron
- Choice of oral iron preparation, such as ferrous sulfate, ferrous fumarate, or ferrous gluconate
- Monitoring of initial haematological response and modification of treatment regimen as needed
- Consideration of parenteral iron in patients who cannot tolerate oral iron or have malabsorption
- Regular hemoglobin monitoring to ensure a satisfactory response.
From the FDA Drug Label
DESCRIPTION Each tablet contains 324 mg of ferrous gluconate, equivalent to 38 mg of elemental iron, providing 211% of the U.S. recommended daily intake (RDI) of iron for adults and children 4 and older. Adult Serving Size: 1 tablet three to four times daily.
The dosing of iron for iron deficiency in adults is 1 tablet three to four times daily, with each tablet containing 38 mg of elemental iron 2.
- The recommended daily dose is between 114 mg and 152 mg of elemental iron.
- This dosing regimen is for oral administration of ferrous gluconate.
From the Research
Dosing of Iron for Iron Deficiency in Adults
- The optimal dosage and frequency of oral iron supplements for iron deficiency in adults is still being researched, with studies suggesting that daily low dose and every other day dosing protocols may be effective in allowing for absorption while limiting side effects 3, 4.
- Oral iron supplementation is usually efficacious in correcting iron-deficiency anemia and replenishing iron stores, but can cause gastrointestinal side effects that reduce compliance 3.
- The simplest and most commonly prescribed oral iron supplement is ferrous sulfate, while other ferrous salts and ferric complexes with polysaccharides or succinylated milk proteins are also widely used 3.
- Novel iron formulations, such as the lipophilic iron donor ferric maltol, or nanoparticle encapsulated sucrosomial® iron, have been developed in recent years 3.
- There is no consensus on the optimal formulation or dosing strategy for oral iron supplements, and further study is needed to advance the care of individuals affected by iron deficiency 4.
- Studies on cardiac aneurysms 5 and total condylar knee prosthesis 6 are not relevant to the dosing of iron for iron deficiency in adults.