Sulphonylurea derivatives enhance the secretion of insulin from pancreatic tissue (β-cells). These drugs can block ATP-dependent potassium channels in the cell membrane of β-cells. The block of the potassium efflux causes a depolarisation of the membrane potential, resulting in an influx of calcium ions.
The policy of treating obese patients with type 2 diabetes mellitus is: first dietary control and losing weight. If this does not result in satisfactory glucose levels the use of biguanides is recommended.
Extra info: Metformin is first choice when dietary control and weight loss fail in reducing glucose levels. When high doses of metformin don't have an effect or the patient cannot tolerate the drug, then sulphonylureas can be applied to decrease the glucose levels.