[Difference between biguanide and thiazolidinedione, and the significance of combination therapy of biguanide and thiazolidinedione].

Insulin resistance is a major pathogenesis underlying the development of hyperglycemia and cardiovascular diseases in type 2 diabetes. Thiazolidinedione (TZD) and biguanide counter insulin resistance, but act by different mechanisms. The two agents are able to lower blood glucose concentrations in type 2 diabetes without occurring overt hypoglycemia and both require the presence of insulin to generate their therapeutic effects, but act without stimulating insulin secretion, and thus have potential cardiovascular benefits beyond glycemic control alone. Combined use of metformin and TZDs has theoretical benefit as it targets two main pathophysiologic defects in type 2 diabetes, such as increased gluconeogenesis and peripheral insulin resistance. Single pill combinations of rosiglitazone/metformin and pioglitazone/metformin have recently been approved for use in the US and Europe.