Hypophosphataemia following iron infusion: a narrative review of an increasingly recognised complication

Parenteral iron is widely prescribed by medical practitioners, with more than 600 000 outpatient prescriptions dispensed in 2025 through the Australian Pharmaceutical Benefits Scheme. While intravenous iron has transformed the management of iron deficiency, hypophosphataemia is now recognised as a common complication, with incidences reported as high as 92% depending on formulation. Although most cases are mild and transient, vulnerable patient groups may develop profound and symptomatic hypophosphataemia, sometimes requiring hospitalisation and intravenous phosphate replacement. The clinical spectrum ranges from subtle biochemical abnormalities to lethargy, weakness and myalgias and, rarely, severe manifestations including muscle weakness, osteomalacia, myopathy, arrhythmias and cardiomyopathy. This narrative review presents five illustrative cases, highlighting the varied presentations of iron-induced hypophosphataemia and potential patient groups at high risk. To address this growing challenge, we present an institutionally endorsed management pathway based on our review of the literature and current practice after multidisciplinary consultation. The algorithm emphasises early recognition of high-risk patients, primary prevention by using formulations of iron associated with the lowest risk of hypophosphataemia, timely identification of symptomatic hypophosphataemia and coordinated correction of concurrent electrolyte disturbances, with the aim of improving patient safety and outcomes.