A popular class of diabetes drugs (thiazolidinediones, or TZDs) which make up a fifth of all prescribed diabetes drugs in the USA, increases patients’ risk of bladder cancer, according to 2012 study published online in the Journal of the National Cancer Institute.
Researchers from the Perelman School of Medicine at the University of Pennsylvania found that patients taking these drugs are two to three times more likely to develop bladder cancer than those who took a sulfonylurea drug, another common class of medications for diabetes.
People with type-2 Diabetes have a 40 per cent increased risk of bladder cancer. These drugs make the situation slightly worse according to the researchers.
The researchers analysed 60,000 Type 2 diabetes patients from the Health Improvement Network (THIN) database in the United Kingdom. They found that patients treated with the TZD drugs pioglitazone (Actos) or rosiglitzaone (Avandia) for five or more years had a two-to-three-fold increase in risk of developing bladder cancer when compared to those who took sulfonylurea drugs.
After 5 or more years, 170 patients per 100,000 would be expected to develop the disease. This compares to about 60 in 100,000 of those who take sulfonylurea drugs, (for example, glipizide or Glucotrol.
Actos is the ninth most commonly prescribed drug in the USA (15 million prescriptions per year). France and Germany have taken the drug off their markets. Another drug Avandia was taken off the market when it became linked to severe cardiovascular problems,
TZDs are commonly prescribed when type-2 diabetes can no longer be controlled with the first option drug Metformin. (The study was funded by the National Institutes of Health.)