[Drug therapy in subjects with impaired glucose tolerance]

Since impaired glucose tolerance (IGT) is a major risk factor for non-insulin-dependent diabetes mellitus (NIDDM), some kinds of intervention aiming to prevent or to delay the onset of NIDDM in subjects with IGT might be considered. Besides life style modification, drug therapy which could correct insulin deficiency and insulin resistance, might prevent progression to NIDDM. One agent is an alpha-glucosidase inhibitor, which delays the absorption of glucose from the intestine. The resulting decrease in postprandial hyperglycemia and hyperinsulinemia could theoretically decrease insulin resistance in IGT subjects and, it is hoped, prevent or delay progression to NIDDM. Metformin, an antihyperglycemic drug of the biguanide class, may be effective in subjects with IGT by reducing hepatic glucose output, enhancing insulin sensitivity, or through other mechanisms such as weight loss. New insulin sensitizers, such as troglitazone and pioglitazone, improve insulin-mediated glucose disposal by enhancing tissue sensitivity to the actions of insulin and reversing the insulin resistance, characteristic of NIDDM. Sulfonylureas might be another candidates of drug intervention to IGT whose insulin secretory abilities are markedly reduced. As far as the question, "Can NIDDM be prevented or delayed?" is concerned, a prospective study using life style modification or above-mentioned drugs, should be performed on long-term basis.