Long-term use of pioglitazone (Actos) might be associated with increased risk for bladder cancer, according to an ongoing drug safety review conducted by the FDA.

The agency looked at 5-year data from a planned 10-year observational study evaluating the potential association between pioglitazone and bladder cancer. Among nearly 200,000 adults with diabetes, overall use of the drug was not associated with a statistically significant increase in cancer risk. However, patients using pioglitazone for longer than 2 years had significantly elevated risk, as did those receiving the highest cumulative doses.

The FDA expects to finish its safety review within a few months. For now, it advises providers to continue prescribing pioglitazone according to the label’s instructions, and to report adverse events to the MedWatch program.