Gliclazide diabetes drug packaging. Gliclazide is an oral hypoglycemic (anti-diabetic drug) that is used to help control blood sugar levels in patients with diabetes. It is a sulphonylurea derivative and is used in the management of diabetes mellitus type 2. Sulphonylureas act by increasing insulin release from the beta cells in the pancreas, which, in turn, reduces the amount of glucose in the blood.