An inadequate response to oral iron therapy may be due to a number of reasons as outlined in the table below with more than one factor often being involved.
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Patient not taking oral iron therapy
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Patient taking an iron supplement or multivitamin tablet with insufficient iron content
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Concomitant consumption of inhibitors of iron absorption (eg, tea, calcium, antacids, tetracycline, within 2 hours of iron ingestion)
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Coexisting inflammation with functional iron deficiency
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Intestinal mucosal disorders (eg, coeliac disease, inflammatory bowel disease)
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Impaired gastric acid secretion (including use of proton pump inhibitors)
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Gastric/intestinal bypass procedures
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Helicobacter pylori colonisation
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Controlled-release iron formulations may contribute (ie, potential for limited iron absorption in some patients)†
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Occult, undiagnosed or recurrent gastrointestinal blood loss (eg, peptic ulcer, malignancy, angiodysplasia, small bowel lesion, parasites)
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Other source of recurrent blood loss (eg, menorrhagia due to uterine pathology or an inherited bleeding disorder such as von Willebrand disorder)
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Multiple sources of recurrent blood loss (eg, hereditary haemorrhagic telangiectasia)
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Ongoing urinary iron losses (eg, significant valve haemolysis)
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Renal failure responding to erythropoietin-stimulating agents
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Superimposed infection, inflammation, malignancy or renal failure
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Concomitant B12 or folate deficiency
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Coexisting primary bone marrow disease or suppression
- Anaemia of chronic disease or renal failure
- Haemoglobinopathy
- Other causes of anaemia (eg, haemolysis, myelodysplastic syndromes, congenital anaemia, endocrine disorders)
Iron-refractory iron-deficiency anaemia (IRIDA) is a recently discovered, rare, autosomal recessive disorder that is unresponsive to treatment with oral iron. It represents less than 1% of the cases of iron-deficiency anaemia seen in medical practice.(2)
*More than one factor is often present. † Role is unclear (limited available data show efficacy comparable to that of non-controlled-release formulations).
Pasricha SR, Flecknoe-Brown SC et al. Diagnosis and management of iron deficiency anaemia: a clinical update. Med J Aust 2010; 193(9): 525-532. © Copyright 2010. The Medical Journal of Australia - reproduced with permission.
References
- Pasricha SR, Flecknoe-Brown SC, Allen KJ, Gibson PR, McMahon LP, Olynyk JK, et al. Diagnosis and management of iron deficiency anaemia: a clinical update. MJA 2010;193:525–532. Available from: http://www.mja.com.au.
- Camaschella C. Iron Deficiency Anemia. N Engl J Med 2015;372:1832-43. Available at: http://www.nejm.org/doi/full/10.1056/NEJMra1401038
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