Are all glitazones the same?

This supplement focuses on the benefits of targeting insulin resistance through therapy with a new class of oral antidiabetic agents, the thiazolidinediones (TZDs) or 'glitazones'. There are important differences between the three TZD class members that warrant discussion to enable physicians to make rational and informed therapeutic choices between the agents. Overall the TZDs appear to be similar in their effects on blood glucose, as all class members have demonstrated effective glycaemic control, both as monotherapy and in combination with sulphonylureas, metformin or exogenous insulin. The safety profiles of the three agents are more diverse, with what appear to be 'TZD class effects', (probably mediated via activation of peroxisome proliferator-activated receptor gamma [PPAR gamma]) and 'TZD-specific effects', which are unique to each agent and may be a consequence of differing chemical structures. While rosiglitazone and pioglitazone share some class effects with troglitazone, they have several characteristics that define them as unique agents. By tackling the control of type 2 diabetes through direct effects on insulin resistance, the TZDs represent an important new therapeutic tool for healthcare professionals.