A new study published in The Archives of Internal Medicine has found that patients taking thiazolidinediones, a class of type 2 diabetes drugs that includes Actos and Avandia, may be at a higher risk of developing vision problems.
The study monitored more than 103,000 patients with type 2 diabetes over a period of about 10 years. Researchers found that those who took either Actos or Avandia had a risk of developing macular edema two to three times higher than those who didn’t use the popular drugs.
The eye disorder occurs when protein deposits collect on or under the central part of the retina, causing it to thicken and swell. Macular edema may distort eyesight and can lead to blindness in one or both eyes.
Researchers found that about 1.3 percent of patients taking Actos or Avandia developed diabetic macular edema, while the condition occurred in just 0.2 percent of the patients not taking one of those drugs. The study also found the risk of developing the eye condition appeared to be heightened even further in patients who took Actos and Avandia in combination with insulin, a practice that is commonly recommended by physicians.
According to the New York Times, study author Dr. Iskandar Idris, a professor of diabetes medicine at the University of Nottingham in England, recommended that patients taking either Actos or Avandia have regular vision checkups, particularly if they are taking one of the drugs in combination with insulin.
Previous smaller trials and reports have suggested a link between thiazolidinediones and vision loss, but not as conclusively as the recently published study.
Other studies have found evidence that Actos and Avandia could cause or worsen congestive heart failure in patients. Actos, made by Takeda Pharmaceuticals of Japan, is the target of a growing number of recent lawsuits filed by patients alleging the drug caused them to develop bladder cancer. Clinical trials have pointed to a heightened risk between Actos and bladder cancer in patients who have used the drug over a year or longer. In June 2011, the U.S. Food and Drug Administration announced it would add bladder cancer to the list of possible risks on Actos drug labeling.