skip to main content

Morphine renal impairment — GPhC CRA MCQ

Instant feedback + full explanation. One question, done properly.

HardCNS TherapeuticsMorphine renal impairmentGPhC CRA

A 78-year-old opioid-naive woman with metastatic breast cancer has stable background pain requiring a long-acting opioid. Her eGFR is 18 mL/min/1.73 m² and a previous low dose of modified-release morphine caused prolonged drowsiness. Following specialist review, which opioid property most strongly favours the proposed alternative?

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

Reveal the answer and explanation

Correct answer: D — Transdermal buprenorphine is not substantially cleared by the kidney

Morphine-6-glucuronide is active and renally eliminated, so it can accumulate and cause prolonged sedation and respiratory depression in advanced renal impairment. Buprenorphine pharmacokinetics are comparatively unaffected by renal failure, making a patch a potential specialist-led option for stable pain. A patch is not suitable for rapidly changing pain or unsupervised opioid initiation. Oxycodone and codeine still require renal caution, while pethidine has a neurotoxic metabolite.

Reference: Morphgesic SR SmPC: https://www.medicines.org.uk/emc/product/4691/smpc; BuTrans SmPC: https://www.medicines.org.uk/emc/product/7645/smpc