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Metformin severe renal impairment — GPhC CRA MCQ

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HardEndocrine TherapeuticsMetformin severe renal impairmentGPhC CRA

A 68-year-old man takes metformin 1g twice daily. His latest results show eGFR 27mL/min/1.73m2, HbA1c 64mmol/mol and ALT within range. He has increasing fatigue but no acute illness. What is the most appropriate alternative?

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Correct answer: E — Contact the prescriber because metformin is inappropriate at this level of renal impairment.

Metformin accumulates in significant renal impairment and increases the risk of lactic acidosis. An eGFR below 30mL/min/1.73m2 is a key threshold requiring discontinuation or urgent prescriber review. Poor glycaemic control should be addressed with safer alternatives.

Reference: BNF; NICE CKS