NICE guidance - metformin in type 2 diabetes

The usual first line therapy in type 2 diabetes management is, in general, modified release metformin plus an SGLT2 inhibitor.

Introducing medicines in a stepwise manner

Medicines should be introduced in a stepwise manner, checking for tolerability and effectiveness of each medicine.

When an adult with type 2 diabetes starts initial therapy with metformin and one or more other medicines:

• introduce the medicines one at a time, starting with metformin and checking tolerability
• if using an SGLT-2 inhibitor, start this as soon as metformin is at the maximum tolerated dose

Reviewing metformin

For adults with type 2 diabetes who are already taking standard-release metformin:

• continue with this treatment or
• switch to modified-release metformin if standard-release metformin is not tolerated or if this is the person's preference
• metformin is contraindicated if a patient has an eGFR of less than 30 mL/min/1.73 m2

For detailed guidance then consult the full guideline.

General guidance re: renal function and metformin

• eGFR ≥45 mL/min/1.73 : safe to use
• eGFR 30–44 mL/min/1.73 : review dose of metformin; consider reducing to a maximum daily dose of 1,000 mg
• eGFR <30 mL/min/1.73 : stop treatment with metformin
• renal risk: Use with caution if there is a risk of rapid deterioration in renal function (e.g., dehydration, infection).

Reference:

• NICE (February 2026). Type 2 diabetes in adults: management