Troglitazone: Antihyperglycemic activity and potential role in the treatment of type 2 diabetes

Insulin resistance is a major component of type 2 diabetes, therefore, an i nsulin sensitizer agent like the thiazolidinedione compound troglitazone is considered a very promising drug. Troglitazone exerts an antihyperglycemic activity in a dose-dependent manner between 200 and 600 mg/day in type 2 d iabetic patients treated with diet alone, sulfonylureas, or insulin. Additi ve antihyperglycemic effect may also be obtained by combining troglitazone and metformin. The antihyperglycemic effect of troglitazone as monotherapy is rather modest (reduction of HbA(1c) by 0.5-1.0%), but it appears to be s omewhat greater when it is combined with other antidiabetic drugs. No doubl e-blind studies have directly compared the activity of troglitazone with th at of sulfonylureas or metformin. Troglitazone has been shown to exert addi tional beneficial effects on serum lipid profile and arterial blood pressur e. It may be considered as a valuable alternative in insulin-resistant (obe se and hyperinsulinemic) diabetic patients who appear to be the best respon ders to the drug. However, the efficacy of troglitazone is challenged by it s safety profile, and the risk of hepatotoxicity still remains a major conc ern in clinical practice.