LAUSR

Metformin, together with lifestyle intervention, is considered first-line treatment for glycemic management in people with type 2 diabetes. Despite this widespread use, one of the areas of longstanding debate has been whether metformin can be used safely in those with chronic kidney disease (CKD). The concern is the possibility of an increased risk for lactic acidosis resulting from metformin accumulation in those with renal impairment. Options in this patient population are limited, and many believe this risk has been overstated, so several organizations around the world have made recommendations to allow for the cautious use of metformin in patients with CKD. Lalau and colleagues have added new evidence with the publication of 3 complementary studies of the use of metformin in people with CKD stages 3A, 3B or 4-a dose-finding study, a chronic metformin treatment study and a pharmacokinetic study. The authors tested adjusted dosage regimens based on level of CKD. The study demonstrates that although there is a relationship between eGFR and metformin levels, there is not a relationship between metformin levels and plasma lactate. In addition, as long as the metformin dosage was adjusted to the level of CKD, pharmacokinetics remained stable. Based on this new evidence, together with past epidemiologic data and systematic reviews, metformin appears to be a safe option for patients with CKD, assuming that the dosage is adjusted individually. Stopping the drug during acute illness is also imperative to ensure its safe use.