Iron Infusions and
Hypophosphatemia
By Associate Professor Chris Barnes
Published May 2023
Iron deficiency anaemia is a common condition that canhave a significant impact on a patient’s quality of life. The incidence of iron deficiency anaemia in Australia is estimated to be 12% in non-pregnant and up to 15% in pregnant females.¹ Iron deficiency without anaemia may be up to three times more common but is often undiagnosed.²
While oral iron therapy is often the first-line treatment, some patients are unable to tolerate it due to gastrointestinal side effects or poor absorption.3 In these cases, iron infusions may be a suitable alternative.
Iron infusion
A common iron infusion therapy in Australia is ferric carboxymaltose (FCM). FCM is a complex of iron and carbohydrate that is administered intravenously and has been shown to be safe and effective in treating iron deficiency anaemia in patients who are unable to tolerate oral iron therapy.⁴
Hypophosphatemia
However, there have been reports of symptomatic hypophosphatemia associated with FCM use. This is a rare condition where the levels of phosphate in the blood are abnormally low, which can cause a range of symptoms including weakness, fatigue, and bone pain. It is thought to occur due to the rapid increase in fibroblast growth factor 23 (FGF23) which increases phosphate secretion. Prolonged hypophosphatemia and associated secondary hyperparathyroidism may be a risk factor for metabolic bone disease, including the development of osteomalacia.
Managing the risk of hypophosphatemia
To help manage this potential risk, doctors may consider monitoring serum phosphate, calcium, vitamin D, and parathyroid hormone (PTH) levels in patients who present with symptoms following FCM infusions. If symptomatic hypophosphatemia occurs, treatment may include phosphate and vitamin D supplementation, along with discontinuation of FCM use.
Despite this potential risk, iron infusions with FCM can offer significant benefits for patients who are unable to tolerate oral iron therapy. By restoring iron levels in the body, patients may experience improved energy levels and improved quality of life. Clinical review and laboratory monitoring for side effects are recommended in patients who present with concerning symptoms following iron infusion.
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References
- Pasricha, S.-R., Flecknoe-Brown, S. C., Allen, K. J., Gibson, P. R., McMahon, L. P., Olynyk, J. K., et al. (2010). Diagnosis andmanagement of iron deficiency anaemia: A clinical update. Medical Journal of Australia, 193(9), 525-32.
- Ioannou, G. N., Rockey, D. C., Bryson, C. L., & Weiss, N. S. (2002). Iron deficiency and gastrointestinal malignancy: A population-based cohort study. Am J Med, 113(4), 276-80.
- Tolkien, Z., Stecher, L., Mander, A. P., Pereira, D. I., & Powell, J. J. (2015). Ferrous sulfate supplementation causes significantgastrointestinal side-effects in adults: A systematic review and meta-analysis. PLoS One, 10(2), e0117383.
- Bailie, G. R. (2010). Efficacy and safety of ferric carboxymaltose in correcting iron-deficiency anemia: a review of randomized controlled trials across different indications. Arzneimittelforschung, 60(6a), 386-98.
About the Author
Associate Professor Chris Barnes
MBBS FRACP FRCPAAssociate Professor Chris Barnes
MBBS FRACP FRCPA- non–malignant haematological conditions including…
- paediatric haematology
Associate Professor Chris Barnes joined Clinical Labs in 2016 and is the National Director of Clinical Pathology. Prior to this, he worked as a consultant haematopathologist with Healthscope Pathology from 2009. Chris is a dual-trained clinical and laboratory haematologist, having trained at the Royal Children’s Hospital and the Royal Melbourne Hospital. He also undertook training at The Hospital for Sick Children in Toronto, Canada. He holds a part-time public hospital appointment at the Royal Children’s Hospital, where he serves as the Director of the Henry Ekert Haemophilia Treatment Centre. Chris has extensive clinical research interests and is the principal investigator on eight separate clinical trials based at the Murdoch Children’s Research Institute. He has held numerous leadership positions, including Chair of the Medical Staff Association at the Royal Children’s Hospital and Chair of the Australian Haemophilia Directors Association. He is currently the Chair of the Australian Bleeding Disorders Registry with the National Blood Authority and a Director of Melbourne Haematology and Melbourne Paediatric Specialists. Chris’ focus within Clinical Labs is the national supervision and management of clinical pathology disciplines, including haematology, biochemistry, microbiology and immunopathology.
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Neutropenia in General Practice
Associate Professor Chris Barnes explains the causes, clinical significance and management of neutropenia, including benign ethnic neutropenia and severe cases.
Iron Deficiency in Women
Associate Professor Chris Barnes discusses the prevalence of iron deficiency in women, its symptoms, diagnostic strategies and effective treatment options.
Managing Vitamin D Deficiency
Dr Phoebe Stanford highlights the role of vitamin D, health risks of deficiency, and guidance on MBS testing and result interpretation.