Both Actos and Avandia have made news as defective drugs because of serious, even life-threatening side effects associated with their use. A new study now links the diabetes drugs to vision problems and potential blindness in addition to increased risks of bladder cancer, heart attack and cardiovascular complications.

Both Actos and Avandia are intended to help reduce the side effects of diabetes, but a new study published in the Archives of Internal Medicine notes that the drugs increase the likelihood of a person with type II diabetes developing macular edema - a swelling of the retina that can cause blindness. Macular edema results when fluid leaks into the macula and can cause blurred vision, floaters and distort the appearance of colors.

Researchers cautioned that, overall, the risk of developing macular edema while taking Actos or Avandia is still relatively small, but it is increased two to three times over those who did not take either diabetes drug. Doctors and physicians are urged to screen for macular edema in patients with type II diabetes who are also taking Actos or Avandia.

The study followed the medical histories of 100,000 individuals over a 10-year period. The study did not take into account any change in the likelihood of developing blurred vision or losing vision entirely after taking Actos or Avandia over an extended period of time. It also did not consider whether the length of time the person affected had been dealing with diabetes.

Those who took aspirin or an ACE inhibitor showed decreased rates of developing vision problems while taking Actos or Avandia. Those who were on an insulin regimen, typical for those suffering from diabetes, were at an even greater risk of developing blurred vision or blindness.

Source: The Dallas Morning News, "Drugs used to treat Type 2 diabetes might increase risk of vision problems," Laura Schwed, June 18, 2012