Contraindications to the use of metformin

According to the United Kingdom prospective diabetes study, patients with type 2 diabetes randomised to intensive treatment with metformin, sulphonylurea, or insulin had similar degrees of glycaemic control and significantly reduced microvascular end points.1 The study showed that the use of metformin in obese patients reduced cardiovascular events. The group treated with metformin had no hypoglycaemia and less weight gain. Treatment with metformin rather than diet alone produced a significant reduction in relative risk in all cause mortality (36%, P=0.011), diabetes related deaths (42%, P=0.017), any diabetes related end point (32%, P=0.0023), and myocardial infarction (39%, P=0.01). Metformin is the only oral hypoglycaemic agent proved to reduce cardiovascular risk and is now recognised as the treatment of choice in overweight patients with type 2 diabetes. Lactic acidosis associated with metformin is a rare condition with an estimated prevalence of one to five cases per 100 000.2 Although classically lactic acidosis associated with metformin has been thought of as lactic acidosis secondary …