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Duration of Bisphosphonate Effect in Hypercalcaemia — SCE Palliative Medicine MCQ

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ModeratePain ManagementDuration of Bisphosphonate Effect in HypercalcaemiaSCE Palliative Medicine

A 65‑year‑old woman with advanced breast cancer has developed symptomatic hypercalcaemia (corrected Ca 3.4 mmol/L) with confusion, dehydration, and constipation. She is rehydrated with IV saline and given zoledronic acid 4 mg IV. After 72 hours, her calcium has normalised (2.45 mmol/L) and symptoms have resolved. How long does the calcium‑lowering effect of zoledronic acid typically last?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: C — The calcium‑lowering effect typically lasts 4–6 weeks; recurrence should be anticipated and a repeat dose planned if symptoms return

Explanation lettering: C = shown as B · E = shown as C · B = shown as E

Option E is correct. UK clinical practice guidance (Kent and Medway Formulary) advises that a single bisphosphonate infusion will usually maintain normocalcaemia for about 3 weeks, emphasising that recurrence is expected and repeat dosing may be needed ([kentandmedwayformulary.nhs.uk](https://kentandmedwayformulary.nhs.uk/media/3p0kpxno/treatment-of-acute-hypercalcaemia-in-adults-2025-alt.pdf?utm_source=openai)). Furthermore, the UK SmPC for zoledronic acid reports a median time to relapse of hypercalcaemia of about 30–40 days, confirming that the effect typically lasts several weeks ([medicines.org.uk](https://www.medicines.org.uk/emc/product/11672/smpc?utm_source=openai)). Distractors: A (exactly 7 days) is overly short and precisely timed—contradicts evidence. B is incorrect—re-treatment is routine and supported. C is wrong—the effect is temporary. D (12 months) vastly overestimates typical duration.

Reference: Kent and Medway Formulary ‘Treatment of acute hypercalcaemia in adults’ (2025) and Zoledronic acid 4 mg SmPC (emc) (UK) – duration of normocalcaemia days to weeks