The pharmacology, pharmacokinetics, clinical efficacy, adverse effects, and dosage and administration of troglitazone are reviewed. Troglitazone is the first oral thiazolidinedione approved for use in treating non-insulin-dependent diabetes mellitus (NIDDM). The drug's mechanism of action has not been fully elucidated. Troglitazone acts as an insulin sensitizer. Cell-line and animal models indicate that troglitazone may decrease hepatic glucose output by decreasing the rate of gluconeogenesis in the liver or by increasing glycolysis. Troglitazone is rapidly absorbed after oral administration, with peak concentration occurring in two to three hours. Food increases absorption by 30-85%. The drug is exten sively metabolized in the liver. Troglitazone has been shown to be efficacious in treating NIDDM, both as monotherapy and in combination with oral sulfonylureas. Patients who are obese or who have high fasting plasma insulin levels may derive the greatest benefit. Patients with impaired glucose tolerance, syndrome X, polycystic ovary syndrome, gestational diabetes, or Werner's syndrome may also benefit from troglitazone. Adverse effects, including hematologic abnormalities, liver toxicity, and hypoglycemia, have been rare in published trials; no life-threatening effects have been reported thus far. The recommended initial dosage is 200 mg once daily with meals, with an increase to 400 mg daily if satisfactory glycemic control is not achieved after two to four weeks. The average wholesale price is $348 for 100 200-mg tablets and $534 for 100 400-mg tablets. Troglitazone may be an effective agent for treating NIDDM, especially in patients who are obese or who have high fasting plasma insulin levels.
