For patients with a creatinine clearance of 45–59ml/min or an eGFR of 45–59ml/min/1.73m2, the initial dose of metformin is 500mg or 850mg once daily in the morning with food. The maximum daily dose is 1g in two divided doses with monitoring of renal function every 3–6 months.
This change to the prescribing information reflects the advice given in the NICE clinical guideline on the management of type II diabetes, namely that metformin can be used with caution in patients with renal impairment but the dose should be reviewed if the patient's eGFR drops below 45ml/min/1.73m2 and treatment discontinued if the eGFR drops below 30ml/min/1.73m2.
The metformin drug entry in MIMS has been updated to reflect the current Glucophage SPCs.
The MIMS drug listings for products containing metformin in combination with other drugs (eg, dipeptidyl peptidase 4 inhibitors, SGLT2 inhibitors, pioglitazone) will be updated when the updated SPCs become available. Prescribers should refer to the product SPCs to check if a combination product is suitable for an individual patient with renal impairment.