skip to main content

Metformin Dental Considerations — MFDS Part 1 MCQ

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

HardHuman DiseaseMetformin Dental ConsiderationsMFDS Part 1

A 68-year-old patient has type 2 diabetes controlled with metformin alone. In which of the following dental scenarios should metformin be temporarily withheld rather than routinely continued?

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

Reveal the answer and explanation

Correct answer: A — Urgent treatment under local anaesthesia when the patient has persistent vomiting, reduced fluid intake and clinical dehydration

The correct answer is A. Vomiting and reduced fluid intake can cause dehydration and acute deterioration in renal function, reducing metformin clearance and increasing the risk of metformin-associated lactic acidosis. The SmPC therefore advises temporary discontinuation and contact with a healthcare professional. A stable eGFR of 42 mL/min/1.73 m² does not itself require complete cessation, although the dose must be appropriate and renal function monitored. Routine local anaesthesia, adrenaline-containing lidocaine and conscious sedation are not independent reasons to stop metformin when hydration and oral intake are maintained. Amoxicillin also does not routinely require metformin withdrawal; however, metformin should be reconsidered if infection becomes severe or causes dehydration, hypoxia or renal deterioration.

Reference: electronic Medicines Compendium. Metformin Tillomed SR 500 mg Prolonged-release Tablets, Summary of Product Characteristics, sections 4.2–4.4. Text revised 2025; eMC updated 2026. https://www.medicines.org.uk/emc/product/102420/smpc