Which diabetes drug carries a known risk of bladder cancer?

• A. Metformin
• B. Gliclazide
• C. Dapagliflozin
• D. Pioglitazone

Answer: (D)

Pioglitazone carries a recognized safety signal for bladder cancer, particularly with long-term use and higher total exposure. This thiazolidinedione can stimulate pathways in bladder tissue over time, and observational data plus regulatory alerts have linked longer duration and higher cumulative doses to an increased risk. Because of this, clinicians weigh the benefits against this potential harm and often reserve pioglitazone for patients where its advantages clearly outweigh the cancer risk, or avoid it in individuals with a history of bladder issues. The other common diabetes medications listed—metformin, gliclazide, and dapagliflozin—do not have a consistent or well-established association with bladder cancer, so they do not carry the same known risk.