Using metformin in the presence of renal disease

In January, the electronic Medicines Compendium (eMC) updated the Summary of Product Characteristics for Glucophage (metformin), approved by the UK Medicines and Healthcare Products Regulatory Agency (MHRA). The summary states that “Metformin may be used in patients with moderate renal impairment, stage 3a (creatinine clearance [CrCl] 45-59 mL/min or estimated glomerular filtration rate [eGFR] 45-59 mL/min/1.73 m²) only in the absence of other conditions that may increase the risk of lactic acidosis . . . If CrCl or eGFR fall <45 mL/min or <45 mL/min/1.73 m² respectively, metformin must be discontinued immediately.”1 This is reiterated in the patient information leaflet.

Interestingly, the summary for generic metformin states that “Renal failure or renal dysfunction (creatinine clearance <60 ml/min)” is a contraindication to use. In the face of burgeoning levels of type 2 diabetes and associated renal disease, we believe that this restriction is too conservative and will deny an important drug to many thousands of people with diabetes who …