Metformin is an antihyperglycemic agent which improves glucose tolerance in patients with type 2 diabetes, lowering both basal and postprandial plasma glucose. Metformin reduces hepatic glucose production by inhibiting gluconeogenesis and glycogenolysis, and stimulates intracellular glycogen synthesis by acting on glycogen synthase. In muscle, it increases insulin sensitivity, improving peripheral glucose uptake and utilization. Metformin also delays intestinal glucose absorption. Metformin increases the transport capacity of all types of membrane glucose transporters (GLUTs) known to date.
In humans, independently of its action on glycemia, metformin has favorable effects on lipid metabolism. This has been shown at therapeutic doses in controlled, medium-term or long-term clinical studies: Metformin reduces total cholesterol, LDL, cholesterol and triglycerides levels. Unlike sulfonylureas, metformin does not produce hypoglycemia in either patients with type 2 diabetes or normal subjects and does not cause hyperinsulinemia. With metformin therapy, insulin secretion remains unchanged while fasting insulin levels and daylong plasma insulin response may actually decrease.
Concomitant use not recommended-
Alcohol: Increased risk of lactic acidosis in acute alcohol intoxication, particularly in case of: fasting or malnutrition, hepatic insufficiency. Avoid consumption of alcohol and alcohol-containing medications.
Iodinated contrast agents: Intravascular administration of iodinated contrast agents may lead to renal failure, resulting in metformin accumulation and a risk of lactic acidosis. Metformin should be discontinued prior to, or at the time of the test and not reinstituted until 48 hours afterwards, and only after renal function has been re-evaluated and found to be normal.