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Metformin renal impairment — GPhC CRA MCQ

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HardEndocrine TherapeuticsMetformin renal impairmentGPhC CRA

A person taking metformin with eGFR 28 mL/min/1.73 m² has diarrhoea, dehydration, abdominal pain, deep breathing and new drowsiness. What is the priority?

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Correct answer: D — Stop metformin and arrange emergency assessment for lactic acidosis

Severe renal impairment and dehydration increase metformin accumulation. Deep breathing, abdominal symptoms and drowsiness are compatible with lactic acidosis and require emergency assessment, including acid–base status, lactate and renal function. Metformin must be stopped rather than merely reformulated.

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