Pioglitazone is an anti-diabetic medication that is used to treat type 2 (non-insulin-dependent) diabetes mellitus. It is a member of the thiazolidinedione (TZD) class of medications, also known as "glitazones." Diabetes type 2 is a condition in which the body either produces insufficient insulin or produces insulin that is not functioning properly. This type of diabetes typically manifests in adulthood.