Avandia, a drug used to treat type 2 diabetes, has been linked to the risk of heart failure and, more recently, heart attack.
GlaxoSmithKline, the maker of the drug, has agreed to add the new warning to the existing black box warning on the drug's label, even though the research on heart attack is inconclusive.
Dr. Janet Woodcock, acting director of the FDA's Center for Drug Evaluation and Research told Health Day News, "We are announcing an update to the existing box warning on Avandia."
"A black box is the strongest form of warning, and we are adding another warning to that black box," he added.
The revised warning will read: Avandia may be associated with "myocardial ischemic events such as angina or myocardial infarction," meaning chest pain or a heart attack. Glaxo is also planning to develop a pamphlet that will come with each bottle putting the warning in easier-to-understand language.
Despite the revised warning label, the FDA said it isn't seeking to have the drug withdrawn from the market, because the evidence for the increased heart-attack risk is not conclusive.
The FDA has asked GlaxoSmithKline to conduct a long-term study comparing Avandia with other type 2 diabetes drugs. The trial will most likely start in a year, and full results won't be available until 2014.
