n. one of a group of *oral hypoglycaemic drugs, derived from a *sulphonamide, that are used in the treatment of type 2 diabetes mellitus; they act by stimulating the islet cells in the pancreas to produce more insulin. The group includes *glibenclamide, *gliclazide, and *tolbutamide. Side-effects, such as nausea, vomiting, and diarrhoea, are usually mild.