Metformin and sulfonylureas
How metformin lowers hepatic glucose output and why its renal clearance drives lactic acidosis and interaction risk, how sulfonylureas close the beta-cell K-ATP channel independent of glucose, and the hypoglycaemia, overdose, monogenic diabetes and kidney questions Paper 1 builds on them.
Tier 1Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Metformin lowers glucose mainly by suppressing hepatic gluconeogenesis. It doesn't raise insulin, so it doesn't cause hypoglycaemia on its own.
- Metformin is not metabolised. It is excreted unchanged by the kidney, so kidney function and tubular transporter interactions set its safety.
- Sulfonylureas close the beta-cell K-ATP channel and release insulin whatever the glucose concentration. Hypoglycaemia and weight gain follow.
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Sources
- Therapeutic Guidelines: DiabetesAU/NZTherapeutic Guidelines Limited, current eTG edition
- Australian Type 2 Diabetes Glycaemic Management AlgorithmAU/NZAustralian Diabetes Society and NDSS, September 2026
- Management of type 2 diabetes: A handbook for general practiceAU/NZRACGP and Diabetes Australia, 2024
- Australian Medicines HandbookAU/NZAustralian Medicines Handbook Pty Ltd, 2026
- Assessment report: metformin and metformin-containing medicines (Article 31 referral), use in patients with reduced kidney functionEuropean Medicines Agency, 2016
- Effect of intensive blood-glucose control with metformin on complications in overweight patients with type 2 diabetes (UKPDS 34)UK Prospective Diabetes Study Group, Lancet 1998;352:854-65, 1998
- Glycemic durability of rosiglitazone, metformin, or glyburide monotherapy (ADOPT)Kahn et al., N Engl J Med 2006;355:2427-43, 2006
- Metformin in women with type 2 diabetes in pregnancy (MiTy): a multicentre, international, randomised, placebo-controlled trialFeig et al., Lancet Diabetes Endocrinol 2020;8:834-44, 2020
- Diabetes management in chronic kidney disease: a consensus report by the ADA and KDIGODiabetes Care (de Boer IH et al., 2022), 2022
- Metformin in gestational diabetes: the offspring follow-up (MiG TOFU), body composition and metabolic outcomes at 7 to 9 yearsBMJ Open Diabetes Research and Care (Rowan JA et al., 2018), 2018
- Last updated
- 14 November 2026
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