Dear sir Glimeperide is a third generation secretogogue, which acts by stimulation of beta cells in the pancreas which increases the endogenous secretion of insulin. But the action of the drugs is subjected to availability of viable beta cells which have a potential to secrete insulin. Secondly as the diabetes progresses the capacity of the beta cells to produce insulin starts decreasing, that is why your old drugs wont work for a long time. Secondly they worked earlier because at the earlier stages you will be having viable beta cells. Consult your doctor and get the different group of drugs to control your blood sugars through different mechanisms like metformin, voglibose etc Thanks