metformin + DPP-4 inhibitor + thiazolidinedione

This is a combination of three **oral antidiabetic agents** used in the treatment of **type 2 diabetes mellitus**: **metformin** (a biguanide), a **DPP-4 inhibitor** (e.g. sitagliptin, vildagliptin), and a **thiazolidinedione** (e.g. pioglitazone). - **Metformin** reduces hepatic glucose production and improves insulin sensitivity in muscle and liver. - **DPP-4 inhibitors** increase endogenous GLP-1 (glucagon-like peptide-1) by inhibiting its breakdown, thereby enhancing insulin secretion and suppressing glucagon release in a glucose-dependent manner. - **Thiazolidinediones** (e.g. pioglitazone) are insulin sensitizers that act as agonists at the peroxisome proliferator-activated receptor gamma (PPARγ), improving insulin sensitivity in adipose tissue, muscle, and liver. This triple combination targets complementary pathophysiologic defects in type 2 diabetes: insulin resistance, impaired insulin secretion, and excessive hepatic glucose production. It is indicated for patients with type 2 diabetes inadequately controlled with dual therapy or monotherapy, aiming for additive and sometimes synergistic effects in glycemic control. The combination is typically used when metformin and a second oral agent have not provided adequate glycemic control. There is no commonly approved single-tablet "fixed-dose combination" available globally for all three components together, but the regimen is used and supported in guidelines and clinical practice for escalation of oral therapy in type 2 diabetes[1][2][4].