Denosumab Hypocalcaemia — RACP Adult Medicine MCQ

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EasyMedical OncologyDenosumab HypocalcaemiaRACP Adult Medicine

A 60-year-old woman with breast cancer develops painful bony metastases. She is commenced on denosumab 120 mg monthly for bone protection. What electrolyte must be monitored and supplemented?

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Correct answer: D — Calcium

Denosumab (a RANKL inhibitor) potently suppresses osteoclast activity, which can cause hypocalcaemia – particularly in patients with CKD, vitamin D deficiency, or hypoparathyroidism. Calcium and vitamin D supplementation is mandatory before and during denosumab therapy. Serum calcium should be checked within 2 weeks of the first dose and periodically thereafter. Severe symptomatic hypocalcaemia requiring hospitalisation has been reported.

Reference: AMH – 2025 – Bone Modifying Agents; eTG – 2025 – Endocrinology