Drugs used to lower blood glucose concentrations in diabetes mellitus.
These oral agents reduce the excessive amounts of glucose in the blood (hyperglycaemia) in people with type 2 (insulin-resistant) diabetes. Although the various drugs act differently, most depend on a supply of endogenous (secreted by the pancreas) insulin. Thus they are of no value in treating patients with type 1 diabetes (insulin-dependent diabetes mellitus [IDDM]), in which the pancreas produces little or no insulin and the patient’s condition is stabilized using insulin injections. The traditional oral hypoglycaemic drugs have been the sulphonylureas and biguanides, but new agents are now available for example, thiazolidine-diones (insulinenhancing agents) and alpha-glucosidase inhibitors, which delay the digestion of carbohydrate and the absorption of glucose. Hypoglycaemic agents should not be prescribed until diabetic patients have been shown not to respond adequately to at least three months’ restriction of carbohydrate intake.