The TZD’s or the thiazolinawhachamacallits…Avandia (rosiglitizone) is the bad boy on the block that no one typically uses anymore due to potential issues with heart failure. Actos (pioglitazone) is nearly always the one that gets used if a TZD is indicated. Primary thing to remember is that they can cause or worsen edema which can be especially problematic in heart failure patients. There are some changes in cholesterol that can happen from Actos, but I don’t necessarily feel that they are clinically significant (i.e. you most likely would not start or stop this drug to based on their cholesterol). These are oral medications like metformin and some others – which is more preferable for most patients. Actos with the heart failure/edema complication I think scares most providers away especially when other options are available. Cost in comparison to much cheaper metformin or sulfonylureas (glipizide) is also a significant issue. A nice advantage is that Actos can be dosed once a day.