Metformin is the most widely used drug for the treatment of type 2 diabetes. This insulin-sensitizing agent has well known beneficial effects not only on glycemic control, but also on the cardiovascular system. The antihyperglycemic effect of metformin is mainly based on suppression of hepatic gluconeogenesis by activation of AMP-activated protein kinase (AMPK), which suppresses glucagon-stimulated glucose production and causes an increase in glucose uptake in muscle and in hepatic cells. Metformin is actively transported across membranes. The organic cation transporter 1 (OCT1) is responsible for uptake of metformin in hepatocytes, which is an essential step in reducing hepatic glucose production. , which is closely associated with its pharmacological action/adverse reactions.