TZDs, for example, offer comparative improvements in hyperglycemia, but have more side effects than other agents. Additionally, evidence for serious adverse events emerged years after this class of drugs had been on the market, thus delaying appropriate recognition. Liver toxicity had been the first serious side effect to be discovered and lead to the withdrawal of troglitazone, and restrictions were temporarily placed on rosiglitazone because of concerns related to increased myocardial infarction risk. TZDs have also been shown to increase the incidence of chronic heart failure (CHF) in select patients 8, bone fractures especially in women, and bladder cancer especially in those receiving therapy for 5 years or longer.