(CBS/ AP) A majority of federal health experts have voted to keep controversial diabetes pill Avandia on market, despite concerns that the drug increases the risk of heart attack compared to other diabetes medications.
A majority of 33 expert panelists said the former blockbuster drug is riskier than older diabetes medicines, including its closest competitor.
The Food and Drug Administration has convened the panel to help untangle reams of conflicting data over whether the drug made by British-based GlaxoSmithKline increases heart risks.
The panel is considering a series of questions culminating with a vote on whether Avandia should be withdrawn from the market.
The FDA is not required to follow the group's advice, although it often does. A final decision will be made in coming months.
In a deposition, former FDA safety reviewer Dr. Rosemary Johann-Liang was asked about the "personal decorum" of an FDA official sharing details about an internal debate with a pharmaceutical executive.
Johann-Liang said this kind of communication should not happen. She said: "I believe there are certain--certain decorums one must abide by when one is regulating an application and deciding upon labeling...".
An FDA spokesperson would not comment on the matter citing ongoing litigation.
Johann-Liang says upon first review of "preclinical data" of glitazones, the class of drug that includes Avandia, she saw "fluid retention of the body that's seen throughout. It's a recurrent story," she said. She described that this can cause "fluid collection like around your ankles and legs..."
Johann-Liang revealed in 2007 that when she pushed for a new severe warning on Avandia she was reprimanded by her superiors.
Dr. Mary Money of Hagerstown, Maryland told CBS News she called the FDA to raise concerns about fluid retention in her patients that were taking Avandia as far back as March 2000. She described one patient's legs as being as swollen as "stove pipes" after taking the drug.
Money says the only response she ever received from the FDA was a form letter that was viewed by CBS News.
An October 7, 2008 internal FDA Avandia review from the Office of Surveillance and Epidemiology released by Senate investigators read: "We conclude that the cardiovascular risks associated with rosiglitazone are excessive...Rosiglitazone should be pulled from the market." The agency did not act on this review.
Despite being reluctant to prescribe the drug, diabetes expert Dr. Robin Goland of Columbia University Medical Center understands Wednesday's decision.
"Having the drug remain on the market continues to allow individual practitioners to weigh the individual risks which are now kind of long against the benefits in an individualized patient," she tells CBS News medical correspondent Jonathan LaPook, M.D.
The FDA has been down this road before. Three years ago a similar FDA panel voted to keep Avandia on the market and the FDA responded by adding bolder warning labels to the drug.
"In terms of what has changed since 2007, I think the totality of evidence is much stronger," said panelist Clifford Rosen of the Maine Medical Research Institute. "It's still not absolute but it's stronger. Clearly there is a signal."
The panel voted 21-4 that Avandia is more likely to cause heart attack than its closest competitor Actos. Eight panelists said there was not enough information to make a decision.
"While I'm not persuaded by the evidence to implicate the drug, I'm also not reassured by the evidence to exonerate it," said Dr. Sanjay Kaul of Cedars-Sinai Medical Center in Los Angeles.
The FDA first approved Avandia in 1999 and it quickly became the top-selling diabetes pill in the world. U.S. sales have plummeted from $2.2 billion in 2006 to $520 million last year as safety concerns swirled around the drug.
Since diabetics are already predisposed to heart risks it is extremely difficult to tell which heart attacks are drug-related and which are simply a result of the underlying disease.
The task of evaluating the possible side effects has dragged on for years without definitive answers.
© MMX, CBS Interactive Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.