Pioglitazone diabetes drug, molecular model. Pioglitazone is a type of thiazolidinedione, a drug used to treat type II diabetes. Patients with type II diabetes are unable to control their blood sugar (glucose) levels. Pioglitazone helps regulate the levels by reducing the amount of glucose the liver releases into the bloodstream and increasing the body's sensitivity to insulin, the hormone that converts glucose to its storage form glycogen. Pioglitazone's chemical formula is C19H20N2O3S. Atoms are represented as spheres and are colour-coded: carbon (C, grey), hydrogen (H, turquoise), nitrogen (N, blue), oxygen (O, red) and sulphur (S, yellow).