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Stopping diabetes medications can result in higher levels of blood sugar that may cause serious short-term health problems. (Muhammad Hamed/Reuters)

Since studies of the diabetes drug Actos suggest an increased risk of bladder cancer for patients taking it for more than a year, Health Canada is reviewing the drug.

The drug pioglitazone is sold under the brand name Actos in Canada,.

This week, the U.S. Food and Drug Administration announced it is adding information on bladder cancer risk to the label of medicines containing pioglitazone and to patient medication guides.

An FDA analysis half way through a 10-year study showed there was no overall increased risk of bladder cancer with pioglitazone use. But there was in patients with the longest exposure to pioglitazone, and in those exposed to the highest cumulative dose of the drug.

Health Canada said Friday that the Canadian product material already includes post-marketing reports of bladder cancer that have been reported very rarely with the use of the drug.

"Health Canada has been closely monitoring this potential risk, and has been reviewing all relevant studies on an ongoing basis. We are taking these studies, including their strengths and limitations, into account as we continue to monitor pioglitazone safety," the department said in a release.

Changing use in Europe

"Should the on-going review identify new safety information, Health Canada will take appropriate action as necessary. This can include updating Canadians with new recommendations regarding pioglitazone and the potential risk of bladder cancer."

A recent study in France also suggested an increase risk of bladder cancer with pioglitazone. Based on those results, France suspended the use of pioglitazone and Germany has recommended against starting pioglitazone in new patients, the FDA said.

The benefits of pioglitazone are considered to outweigh the risks when used as directed, Health Canada said.

In response to this FDA's announcement, The Endocrine Society, the American Association of Clinical Endocrinologists and the American Diabetes Association urge patients who are currently taking Actos or any combination of medication that includes pioglitazone to continue taking all currently prescribed medications unless instructed otherwise by their healthcare provider.

Stopping diabetes medications can result in higher levels of blood glucose that may cause serious short-term health problems and could increase the risk of diabetes-related complications in the long term, the groups said.