Current role of metformin in treatment of diabetes mellitus type 2

Metformin-associated lactic acidosis is not necessarily due to metformin accumulation. It appears that mortality in patients receiving metformin who develop lactic acidosis is mostly linked to underlying disease. It has been suggested that metformin should be the first-line agent for the treatment of obese type 2 diabetic patients since metformin was associated with a significant decrease in macrovascular events and a reduction of all-cause mortality in the United Kingdom Prospective Diabetes Study (UKPDS) in a substudy. However, in this substudy no significant decrease in microvascular complications was observed in obese subjects with intensive metformin therapy. In addition, the use of metformin in combination with sulfonylurea seemed to be associated with excess risk of diabetes-related and all-cause mortality in obese subjects. Due to the discrepant and contradictory nature of the results in the obese patients and a lack of power the UKPDS offered no decision for any drug for initial therapy of type 2 diabetes. The main message of the UKPDS is that lowering of the blood glucose to the normal range is beneficial irrespective of the hypoglycaemic agent used. A rational approach to therapy in a type 2 diabetes patient who fails to sufficiently lower blood sugar with diet and weight loss is to begin therapy with a sulfonylurea or metformin and to add another oral agent if the desired glycaemic control is not achieved.