Troglitazone (TGZ, brand name: Rezulin and Prelay) is a peroxisome proliferator-activated receptor gamma (PPAR gamma) ligand, which was developed by Daiichi Sankyo and approved for the US market for the treatment of Type II diabetes mellitus. The drug is used alone or in combination with a sulfonylurea, metformin, or insulin as an adjunct to diet and exercise, and was not indicated as initial therapy in patients with type 2 diabetes. This drug was withdrawn from the UK market due to liver toxicity. It was removed from the US market in 2000, only 3 years after its introduction and from Japan, shortly afterward. In addition, was conducted a clinical trial for the treatment of patients with advanced liposarcoma by using troglitazone, but the positive result wasn’t obtained. It was shown, that in case of cancer cells troglitazone acted independently of PPAR gamma, by up-regulation of early growth response-1 (Egr-1). Egr-1 transcription factor has been linked to apoptosis and shown to be activated by extracellular signal-regulated kinase (ERK).
Originator
Approval Year
Sample Use Guides
Prelay (TROGLITAZONE tablet) should be taken with a meal.
Combination Therapy:
Sulfonylureas: Prelay in combination with a sulfonylurea should be initiated at 200 mg once daily. The current sulfonylurea dose should be continued upon initiation of Prelay therapy. For patients not responding adequately, the Rezulin dose should be increased at 2 to 4 weeks. The maximum recommended dose is 600 mg once daily. The dose of sulfonylurea may require lowering to optimize therapy.
Metformin: For patients not responding adequately to metformin and sulfonylurea therapy, 400 mg daily of Prelay may be added.
Insulin: The current insulin dose should be continued upon initiation of Prelay therapy. Prelay therapy should be initiated at 200 mg once daily in patients on insulin therapy. For patients not responding adequately, the dose of Prelay should be increased after approximately 2 to 4 weeks. The usual dose of Prelay is 400 mg once daily. The maximum recommended daily dose is 600 mg. It is recommended that the insulin dose be decreased by 10% to 25% when fasting plasma glucose concentrations decrease to less than 120 mg/dL in patients receiving concomitant insulin and Prelay. Further adjustments should be individualized based on glucose-lowering response.
Patients With Renal Insufficiency: Dose adjustment in patients with renal insufficiency is not required
Route of Administration:
Oral
Human HCC cell lines Huh7 and Hep3B were cultured in the presence or absence of troglitazone. Cell growth was determined via WST-1 assay, proliferation by cell cycle analysis and proliferating cell nuclear antigen (PCNA) Western blotting, and apoptosis by flow cytometry and TUNEL. In cultures of Hep3B and Huh7 cells, basal expression of PPARgamma was relatively low, but troglitazone caused dose-dependent induction of PPARgamma expression.
