Glibenclamide is an antidiabetic drug in a class of medications known as sulfonylureas, closely related to sulfa drugs. The drug works by binding to and activating the sulfonylurea receptor 1 (SUR1), the regulatory subunit of the ATP-sensitive potassium channels (KATP) in pancreatic beta cells. This inhibition causes cell membrane depolarization opening voltage-dependent calcium channel. This results in an increase in intracellular calcium in the beta cell and subsequent stimulation of insulin release. Glibenclamide may be contraindicated in for those with G6PD deficiency, as it may cause acute haemolysis. Recently published data suggest glibenclamide is associated with significantly higher annual mortality when combined with metformin than other insulin-secreting medications, after correcting for other potentially confounding patient characteristics. The safety of this combination has been questioned.