Denosumab Hypocalcaemia in CKD — RACP Adult Medicine MCQ

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ModerateMedical OncologyDenosumab Hypocalcaemia in CKDRACP Adult Medicine

A 65-year-old woman with breast cancer develops bone metastases and commences denosumab 120 mg monthly. She has CKD stage 4 (eGFR 18 mL/min/1.73 m²). What is the most important adverse effect to monitor in this patient?

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Correct answer: D — Severe hypocalcaemia

Denosumab does not require renal dose adjustment (unlike zoledronic acid), making it preferred for bone metastases in patients with CKD. However, severe hypocalcaemia is significantly more common in patients with CKD, particularly CKD stage 4–5. Pre-existing vitamin D deficiency exacerbates this risk. Calcium and vitamin D supplementation is mandatory, and serum calcium should be checked within 2 weeks of the first dose and regularly thereafter. Fatal hypocalcaemia has been reported.

Reference: AMH – 2025 – Denosumab; eTG – 2025 – Endocrinology