Gliphenylurea is a second-generation sulfonylurea glucose-lowering compound. Second-generation sulfonylureas also include glipizide, gliclazide, and glimepiride. They are more effective than the first generation of toluenosulfonylurea. Generally, when used alone, glibenclamide is used at
4
hours to peak, food digestion does not prevent absorption of the drug as well as its metabolism in the liver, with comparable levels of metabolites in bile and urine. Second generation drugs are relatively safe. The main side effect of glibenclamide, is dose related severe hypoglycemia. Hypoglycemia is more likely to occur in older patients than in younger people. Therefore, it is best to stop taking gliphenylurea in people over 60 years of age. Glimepiride, a relatively new class of sulfonylurea hypoglycemic agents, is still a second-generation hypoglycemic agent. Glimepiride and glibenclamide can replace one another at their respective binding sites. In contrast to glibenclamide, glimepiride has the ability to bind from the β
sulphonylurea receptor (SUR) binding site by a factor of 2.5-3 and 8-9
times faster dissociation. This results in shorter duration of insulin secretion and faster release. At the same time glimepiride increases insulin secretion, systemic glucose uptake and insulin sensitivity in the second time phase. Glimepiride is much less likely to cause severe hypoglycemia than gliphenylurea.