The GlaxoSmithKline (GSK) headquarters compound in west London. Controversy over diabetes drug Avandia heated up Wednesday as experts pointed to studies linking it to greater heart attack risk, while a GSK study claimed rosiglitazone is safe. (File Photo)

    BEIJING, June 8 (Xinhuanet) -- The U.S. Food and Drug Administration has asked that two controversial type 2 diabetes drugs carry a "black box" warning on the potentially heightened risk of congestive heart failure in some patients, according to media reports Thursday.

    There's already a warning on the drug's label that Avandia raises the risk of heart failure in some patients but the FDA said it is asking for a more prominent "black box" warning. The agency also said it has asked the maker of a similar drug, Actos, to apply the same warning. Actos is made by Takeda Pharmaceutical Co. and is co-marketed in the U.S. by Eli Lilly & Co..

    The FDA's comments were made in the written testimony of FDA Commissioner Andrew von Eschenbach that was prepared for a U.S. House hearing looking at the FDA's role in evaluating safety issues with the drug.

    The current safety debate, however, isn't whether Avandia increases the heart failure risks but is focusing on more recent data suggesting it increases the risks for heart attacks. Heart failure is typically a condition that develops over time and characterized by the heart's inability to properly pump blood.

    In von Eschenbach's testimony, he said the agency sent letters to the makers of Avandia and Actos requesting a so-called black-box warning in the drugs to "more prominently address the risks of congestive heart failure associated with the use of these drugs in certain patients." Von Eschenbach said despite existing warnings, the drugs were still being prescribed to patients with heart failure.

    Last month, an analysis of 42 relatively short-term studies by prominent Cleveland Clinic cardiologist Steven Nissen -- published online at the New England Journal of Medicine site -- found Avandia increased the risk of heart attacks by 43 percent%. That news prompted Rep. Henry Waxman, D-Calif., chairman of the House Oversight and Government Reform Committee to call a hearing that largely focused on the FDA's role in evaluating the post-market safety of Avandia.

    (Agencies)