Heading into 2007, Avandia was one of the best selling prescription medications in the United States. However, a string of negative studies may change that. Recent studies have linked the diabetes drug to heart attacks and bone fractures. More troubling to Glaxo Smith Kline, Avandia's manufacturer, is that the competing drug Actos appears to be safer than Avandia.

In May, 2007 the Cleveland Clinic issued a study which showed that patients taking Avandia had a 43% greater risk of suffering a heart attack. The study which was published in the New England journal of Medicine, reviewed more than 40 clinical studies involving 28,000 patients. Dr. Steven Nissen, who led the study, estimates that tens of thousands of people have had heart attacks as a result of Avandia. The news even surprised the ADA (American Diabetes Associates) which urged doctors to be more cautious when deciding to prescribed Avandia.

Before the Cleveland Clinic study was ever published, the company conducted its own internal study which revealed an increased risk of heart attacks. Glaxo Smith Kline informed the Food and Drug Administration about the cardiovascular risk but never told Avandia patients or doctors prescribing Avandia.

As a result of the Cleveland Clinic study and the internal Glaxo Smith Kline analysis, the FDA convened a special panel to discuss the cardiovascular risks associated with Avandia. This panel voted 20-3 that the drug did, in fact, raise the chance of heart attacks. However the FDA stopped short of removing the drug from the market, voting 22-1 to allow Glaxo Smith Kline to continue marketing the drug. However the panel recommended that Glaxo Smith Kline include a new warning on Avandia's warning label about heart attacks and other cardiovascular risk.

On November 14, 2007 the FDA issued a press release announcing that Glaxo Smith Kline had agreed to add new language to its existing black box warning on Avandia about the increased risk for heart attack. A black box warning is the strongest warning the FDA can issue. Avandia has already had a black box warning about the risk of Congestive Heart Failure.

While the black box warning about heart attacks was troubling for Avandia, the negative news continued. A recent study revealed that the popular diabetes drug may be linked to osteoporosis and other debillatating side effects. Researchers found that Avandia affects a key cellular protein that can stimulate the production of cells which aggressively degrade bone. Since many Avandia patients are at an age where osteoporosis is already a concern, the authors of the study recommend that Avandia should be prescribed with caution.