Oral Iron Supplementation Remains Gold Standard in Anemia Care

Iron-deficiency anemia occurs when there is not enough iron in the body, which can be caused by blood loss due to injury or surgery, as well as use of some medications, according to the National Heart, Lung, and Blood Institute.¹ Additionally, iron absorption can be limited by conditions related to digestion, kidney disease and inflammation, or genetics.¹

A ferritin blood test is the most common way to diagnose iron deficiency, although recommended thresholds vary. A recent guideline from the American Gastroenterological Association recommends a ferritin cutoff of 45 mg/dL in individuals with anemia because this level is believed to have an ideal balance between sensitivity and specificity.²

Maintaining iron levels by consuming foods rich in iron and vitamin C is ideal, but supplementation or intravenous iron can also help increase iron levels when needed. If left untreated, iron deficiency can cause fatigue, headaches, restless legs syndrome, cardiovascular issues, and pregnancy complications, and may also worsen other chronic conditions.¹

Iron binds to hemoprotein, with approximately two-thirds of the body’s iron found in hemoglobin, 25% in mobilizable iron stores, and 15% in muscle tissue myoglobin and oxidative metabolism enzymes. Iron absorption typically ranges from approximately 5% to 35%. Plant-based diets can inhibit iron absorption because phytates limit absorption of minerals and nutrients. Calcium polyphenols and some animal proteins, including milk, eggs, and albumin, can also inhibit absorption.³

CONSIDERATIONS FOR PATIENTS WITH INFLAMMATORY CONDITIONS

Iron deficiency associated with inflammatory conditions such as inflammatory bowel disease or celiac disease can require more consideration. Importantly, patients with inflammatory conditions may have iron deficiency or iron-deficiency anemia even with a ferritin level greater than 45 mg/dL, although typically less than 100 mg/dL.²

The American Gastroenterological Association Clinical Practice Update on Management of Iron Deficiency Anemia recommends the supplementation of iron with OTC products. Patients with iron-deficiency anemia associated with inflammatory bowel disease should be evaluated for inadequate intake of iron, inadequate absorption, or loss of iron due to gastrointestinal bleeding. Active inflammation should be treated to enhance absorption or reduce depletion. Additionally, oral iron supplements should be used for individuals with portal hypertensive gastropathy. For patients with celiac disease, absorption can be improved through a gluten-free diet, and oral iron supplementation should be considered based on the severity of deficiency and patient tolerance.²

PHARMACISTS’ ROLES

A literature review and focus group study found that pharmacists are closely involved in screening and detection, medication management and selection, patient counseling and education, and ongoing monitoring. In the focus group, participants emphasized that there is a significant need for guidelines or toolkits designed for pharmacists.⁴

Recommendations can vary based on patients’ age, sex, and whether they are pregnant. However, there are a few challenges with oral iron, including nonadherence, which authors of a review published in HemaSphere consider to be the most significant cause of nonresponse or recurrent iron deficiency. Additionally, adverse events (AEs) can include abdominal pain, constipation, nausea, vomiting, and diarrhea, further making adherence difficult. Novel therapies have been designed to improve absorption and reduce gastrointestinal AEs, including sucrosomial iron and iron hydroxide adipate tartrate.⁵

Importantly, oral iron increases levels of serum hepcidin for up to 48 hours, so there is no reason to take supplementation daily. Some early data suggest that iron supplements taken every other day could improve tolerance, but this approach needs further research. Furthermore, taking an iron supplement with a meat protein or with vitamin C can strengthen iron absorption.²

REFERENCES

1. National Heart, Lung, and Blood Institute. Anemia: iron-deficiency anemia. March 24, 2022. Accessed July 18, 2024. https://www.nhlbi.nih.gov/health/anemia/iron-deficiency-anemia

2. DeLoughery TG, Jackson CS, Ko CW, Rockey DC. AGA Clinical Practice Update on Management of Iron Deficiency Anemia: expert review. Clin Gastroenterol Hepatol. Published online June 11, 2024. doi:10.1016/j.cgh.2024.03.046

3. Abbaspour N, Hurrell R, Kelishadi R. Review on iron and its importance for human health. J Res Med Sci. 2014;19(2):164-174. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3999603/

4. Meilianti S, John C, Duggan C, O’campo L, Bates I. How can pharmacists contribute to anaemia management: a review of literature and exploratory study on pharmacists’ role in anaemia. Explor Res Clin Soc Pharm. 2023;9:100231. doi:10.1016/j.rcsop.2023.100231

5. Iolascon A, Andolfo I, Russo R, et al. Recommendations for diagnosis, treatment, and prevention of iron deficiency and iron deficiency anemia. Hemasphere. 2024;8(7):e108. doi:10.1002/hem3.108