Delayed-onset hypocalcaemia and hypophosphataemia induced by iron infusion in the context of denosumab therapy

Hypocalcaemia and hypophosphataemia are recognised complications of concurrent denosumab and parenteral iron therapy, typically occurring within weeks of administration. We report a case of delayed-onset hypocalcaemia and hypophosphataemia following an iron infusion 5 months post denosumab administration in a postmenopausal woman with chronic kidney disease. This interaction induced profound hypocalcaemia and hypophosphataemia, despite normal preinfusion electrolyte and hormone levels. Clinicians should be aware of the potential for late-onset electrolyte disturbances in patients on denosumab, particularly when administering treatments that could interact with bone metabolism. Timely recognition is essential for effective management.