Thiazolidinediones (TZD) are effective agents for the treatment of hyperglycemia, and appear ideal in diabetic patients with progressive or end-stage renal disease because of its predominant hepatic clearance. Troglitazone, the first available TZD for clinical use, was withdrawn due to safety concerns; however, studies completed with this agent can provide a better understanding of the class effect of TZDs. This study was an open-label, controlled clinical trial examining the safety and efficacy of troglitazone in type 2 diabetic patients with end-stage renal disease (ESRD). Twelve subjects were randomized to parallel study groups and treated for 6 mo with or without troglita-zone at a maximum dose of 600 mg/d in addition to continuing their previous diabetes medications (insulin or sulfonylurea). The results showed no significant differences in glycemic control with or without troglit-azone treatment for 6 mo. However, there was a significant reduction in insulin dosage with troglitazone treatment (22.9 +/- 7.3 units/d) than without troglita-zone treatment (54 +/- 12.9 units/d) (p < 0.05), as well as the change in the insulin dosage from baseline between the two groups (troglitazone, -8.4 units vs control, +4.3 units, p < 0.05). Weight changes and aspartate amino-transferase levels greater than 1.5 times the upper limit of normal were not observed in participants of either treatment group. This study demonstrates that troglit-azone was safe and effective for the treatment of hyper-glycemia in patients requiring dialysis, and strongly supports the clinical use of currently available TZDs in diabetic patients with renal failure.