[Proposal for the modification of metformin use in patients with chronic kidney disease]

Metformin is the first-line, widely used oral antidiabetic agent for the management of type 2 diabetes. There is increasing evidence that metformin use results in a reduction in cardiovascular morbidity and mortality, and might have anticancer activity. An extremely rare, but potentially life-threatening adverse effect of metformin is lactic acidosis, therefore, its use is traditionally contraindicated if the glomerular filtrate rate is below 60 mL/min. However, lactic acidosis is always associated with acute events, such as hypovolemia, acute cardiorespiratory illness, severe sepsis and acute renal or hepatic failure. Furthermore, administration of insulins and conventional antihyperglycemic agents increases the risk of severe hypoglycemic events when renal function is reduced. Therefore, the magnitude of the benefit of metformin use would outweigh potential risk of lactic acidosis in moderate chronic renal disease. After reviewing the literature, the authors give a proposal for the administration of metformin, according to the calculated glomerular filtrate rate.