Actos 30mg tablet; image courtesy of

In a press release issued yesterday the FDA adds new warnings about Actos and bladder cancer risk. The diabetes drug pioglitazone, sold as Actos, Actoplus Met, Actoplus Met XR, Duetact and Oseni could increase patients’ risk of developing bladder cancer, prompting the Agency to uphold current label warnings in addition to adding new ones.

Following a long-term study of pioglitazone’s safety, the FDA’s first warnings were issued in September 2010 and June 2011. The first warnings were added to the drugs’ labels in August 2011. The Agency also mandated that the manufacturers modify and continue a 10-year epidemiologic study into the risks involved.

Chart showing bladder cancer; image courtesy of
Chart showing bladder cancer; image courtesy of

Pioglitazone is sold as a generic in addition to Actos and several other drugs, as well as in fixed-dose combination drugs, often containing metformin. The drug is currently used to help improve type 2 diabetes patients’ blood glucose control. It works by increasing the patients’ insulin sensitivity.

The FDA reviewed several, sometimes contradictory, studies before issuing the new warnings. Some of the studies showed a possible link between pioglitazone and a greater risk of bladder cancer while others showed no connection at all. Some found an increased risk of bladder cancer during the trial period, but not the follow-up period.

After this review, the Agency said, “Some studies found an increased risk of bladder cancer with pioglitazone use and others did not…. Overall, we conclude that pioglitazone may be associated with an increased risk in urinary bladder cancer, and we have updated the drug labels to include information about these additional studies.”

The FDA decided the new warnings were warranted despite a 10-year study by Takeda, the maker of Actos that showed no increased risk of bladder cancer. Another of the studies the Agency reviewed, an independent European study, also showed no increased risk of bladder cancer.

Among the studies reviewed was a British study that showed a slight risk of developing bladder cancer in patients using pioglitazone as opposed to other anti-diabetic drugs.

Though the reviewed studies do not conclusively prove that pioglitazone use increases patients’ risk of developing bladder cancer, the FDA believes enough evidence exists to support the Agency’s original conclusion and the new warnings. The Agency is recommending that those patients with bladder cancer or a history of bladder cancer be treated with something other than pioglitazone-containing medications.

Patients currently taking a pioglitazone-containing medication should watch for symptoms of bladder cancer and call their health care provide immediately if they notice such symptoms. The symptoms include:

  • Painful urination
  • Red-tinted (blood) in urine
  • New or worsening urges to urinate

The Agency is also asking that patients and health care providers who are experiencing or are told of such adverse events report them vial the FDA’s MedWatch Safety Information and Adverse Event Reporting Program.


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