Avandia Linked to Vision Loss

April 3, 2009. By Heidi Turner

Philadelphia, PA: As if patients taking Avandia did not have enough to worry about already, what with the severe Avandia side effects including an increased risk of heart problems. Now, a study has found a link between the use of glitazones, the class of drug that Avandia falls into, and diabetic macular edema (DME)—a vision problem. So, patients who take the diabetes medication have to worry about an Avandia heart attack, liver failure and vision problems, but there still has been no announcement of an Avandia recall.

The study was recently published in the American Journal of Ophthalmology and used a database of 170,000 people with diabetes. Researchers then studied the link between the use of glitazones and the onset of DME, which is a common complication of diabetes. DME results in swelling and fluid build-up in the retina and can cause progressive loss of vision.

Researchers found that patients who took glitazones were 2.6 times more likely than patients not taking the drugs to develop DME. Remember, even though DME is a common occurrence in patients with diabetes, all those included in the survey had diabetes and those who took glitazones still had an increased risk of developing DME. Furthermore, researchers adjusted for other factors that might cause DME and still found that those who took the glitazones had a 60 percent higher risk of developing the condition.

Glitazones have already been linked to heart failure, which is related to fluid retention and edema. DME can be made worse by fluid retention from heart failure. In their conclusion, researchers noted, "The current study appears to show that the glitazone class of drug is associated with DME…When treating patients with DME, ophthalmologists should consider the role of the glitazones."

The risk of vision problems associated with Avandia has been known for a few years. In 2006, the FDA warned about the risk of DME in patients taking the diabetes drug. At the time, the risk was said to be rare, however the results of this study suggest that those risks may not be as rare as suggested.

So now, in addition to the risk of heart attacks and bone fractures, patients taking Avandia must be concerned about serious vision problems. And still Avandia stays on the market, despite the availability of older drugs that are less expensive and, reportedly, just as effective without the side effects.

Advocacy groups, including Public Citizen, have called for a ban on Avandia because of its serious side effects, including liver failure. Even the American Diabetes Association has come out against the use of Avandia.

"The scientific consensus against Avandia is overwhelming," said Dr. Sidney Wolfe, director of Public Citizen's Health Research Group in a 2008 statement. "The timing of these findings [linking Avandia to liver failure] should give the FDA the momentum it needs to act swiftly to prevent further needless deaths and health damage by banning this drug." However, so far, no action has been taken to remove Avandia from the market.

Because vision loss and DME are associated with diabetes, patients may not have known that their vision problems could have been related to the use of Avandia and other glitazones. Symptoms of macular edema include blurry or distorted vision, poorer adaptation to the dark and decreased color sensitivity. If you develop any of those problems seek medical attention.

Lawsuits have been filed against GlaxoSmithKline, alleging the company put profits before people and failed to warn patients about the risks associated with Avandia.