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Methotrexate trimethoprim — GPhC CRA MCQ

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HardMusculoskeletal TherapeuticsMethotrexate trimethoprimGPhC CRA

An 80-year-old woman weighing 60 kg has serum creatinine 120 micromol/L and is prescribed zoledronic acid 5 mg IV for osteoporosis. Cockcroft–Gault creatinine clearance is approximately 31 mL/min. What should the pharmacist do?

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

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Correct answer: E — Withhold and query: the calculated CrCl is below the 35 mL/min threshold

For the 5 mg osteoporosis preparation, MHRA advises measuring renal function before treatment and not using it when creatinine clearance is below 35 mL/min. Hydration and slower administration reduce risk but do not remove the stated contraindication. The pharmacist cannot invent a 2.5 mg osteoporosis dose or substitute an oral bisphosphonate without a lawful prescribing decision.

Reference: MHRA: intravenous zoledronic acid and renal function. https://www.gov.uk/drug-safety-update/intravenous-zoledronic-acid-adverse-effects-on-renal-function