Metformin

Metformin is one of the oldest antidiabetic drugs for the treatment of type 2 diabetes. It remains first line in most international guidelines for people with type 2 diabetes who are unable to maintain target glycaemia with lifestyle measures alone. Metformin works primarily by reducing hepatic gluconeogenesis and sensitising peripheral tissues to the effects of insulin. It is a safe and effective drug with proven cardiovascular benefits. Metformin does not cause weight gain or hypoglycaemia and may be associated with weight loss. While gastrointestinal side effects are common and can limit its use in some people, lactic acidosis is the most important side effect of metformin but is rare. The role of metformin remains central to the management of people with type 2 diabetes, whereas the role of metformin in people with type 1 diabetes and in preventing type 2 diabetes remains uncertain. It is likely that metformin may yet have novel roles in the management and prevention of diabetes and its complications.