Can metformin be used in chronic kidney disease?
Metformin may be suitable for some people with kidney disease, depending on eGFR and clinical stability. It is contraindicated below 30 mL/min/1.73 m²; a result above that level does not automatically make starting it appropriate.
Details
Starting differs from continuing
U.S. labelling does not recommend starting metformin at eGFR 30–45. For people already taking it, benefits and risks are reassessed when eGFR falls below 45. Specialty guidelines support selected use with dose reduction and renal monitoring. The clinician must reconcile guidance with local labelling and your circumstances.
What can change the decision?
Severe dehydration or acute kidney deterioration can increase drug accumulation risk. Ask for a sick-day plan for vomiting, diarrhoea or reduced fluid intake. Tell the radiology team before iodinated contrast; some circumstances require temporary interruption and reassessment.
Preparing for review
Bring recent kidney tests, your medicine list and current dose. Do not start or restart metformin using an old result, or change the dose from an online table without medical advice.
Related reading: When does someone with diabetes need insulin?.