Some of the newer drugs such as repaglinide lower blood sugar more quickly and for a shorter period of time than the older formulations and may require more frequent doses. However, it is thought that their activity may more closely mimic the natural fluctuations of insulin secretion that occur with fasting and feeding. The oral hypoglycemics stimulate the pancreas to secrete insulin. This requires the presence of functioning insulin producing cells, so they are ineffective in type I diabetics . Some of them also decrease the production of glucose by the liver, increase the insulin sensitivity of target cells, and decrease the levels of cholesterol and triglycerides transporting molecules in the blood.
Many drugs can interact with the oral agents.
Oral hypoglycemics are usually well tolerated. The main side effect occurs when the blood sugar is decreased in excess, referred to as hypoglycemia. It can be severe, and may manifest as hunger, nausea, fatigue, perspiration, headache, palpitations, numbness of the mouth, tingling in the fingers, tremors, blurred vision, mental confusion, or loss of consciousness. Hypoglycemia may result from a high dose of a hypoglycemic agent but can also be due to poor food intake, excessive exercise, or a drug interaction. It inhibits the alpha-glucosidase enzymes that reside in the intestine at the sites where most nutrient absorption occurs.