Actos (pioglitazone) is an oral diabetes medication in the class of drugs known as the thiazolidinediones (TZD). Diabetes is a disease in which the pancreas does not make enough insulin to control the level of glucose in the blood or when the body is unable to use insulin effectively.
Although Actos is currently in the spotlight, it is not the only diabetes drug that has come under scrutiny for causing an increased risk of harm. Another member of the pioglitazone class, Rezulin (troglitazone), caused serious liver damage leading to its withdrawal in 2000, less than 3 years after its marketing. The use of the 2 other TZDs, Avandia (rosiglitazone) and Actos (pioglitazone), sharply increased during the past several years and each appear to present a lower risk of liver damage than Rezulin. However, each has been shown to cause its own different toxicity. Avandia has been recognized to be associated with fluid retention and an increased risk of congestive heart failure (CHF). Actos, while also associated with CHF, has recently been linked with bladder cancer. Recently, the European Medicines Agency suspended the marketing of Avandia and the FDA largely restricted its usage thereby leading to an increase usage of the sole TZD remaining, Actos.
A link between Actos and bladder cancer first appeared in preclinical animal studies. In a large clinical trial called PROactive 2.5 times as many participants exposed to Actos developed bladder cancer as did those given a ‘placebo’.
In September 2010 the FDA announced that further study would be performed and the manufacturer of Actos would conduct a 10-year long observational study to address to address the long-term risk of bladder cancer. In addition, another study was published this year looking at the relationship between Actos and bladder cancer by reviewing reports found within the FDA’s Adverse Events Reporting System (AERS). They found “a de?nite signal for bladder cancer associated with (Actos) use.” The signal was strongest, as expected, in older men but women were also found to have a risk 5 times greater than those not taking the drug. The length of drug use was reported to be 6 months in 6 patients, 6 to 24 months in 5 patients and 24 months in 4 patients.