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Metformin in renal impairment — GPhC CRA MCQ

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HardEndocrine TherapeuticsMetformin in renal impairmentGPhC CRA

A patient taking metformin 500 mg twice daily has a confirmed eGFR of 22 mL/min/1.73 m² while clinically stable. What recommendation is required?

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Correct answer: C — Stop metformin and select an alternative glucose-lowering strategy

Metformin is not used when eGFR is below 30 mL/min/1.73 m² because accumulation increases lactic-acidosis risk. The prescriber should stop it and select treatment suited to glycaemic need, comorbidity and renal function; abrupt insulin substitution is not automatically required.

Reference: BNF: metformin hydrochloride: https://bnf.nice.org.uk/drugs/metformin-hydrochloride/