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Metformin renal impairment — GPhC CRA MCQ

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HardEndocrine TherapeuticsMetformin renal impairmentGPhC CRA

A 70-year-old woman taking metformin 1g twice daily has a routine eGFR result of 28mL/min/1.73m2. She also reports poor appetite and diarrhoea after a recent gastroenteritis episode. What monitoring is required?

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Correct answer: A — Withhold supply and urgently ask the prescriber to review metformin safety

Metformin requires review or discontinuation in significant renal impairment because of lactic acidosis risk. Acute illness with diarrhoea and reduced intake adds further risk of dehydration and kidney deterioration. The pharmacist should not substitute another antidiabetic medicine independently. Prompt prescriber review is appropriate before continued supply.

Reference: BNF; NICE CKS Diabetes type 2