(Adds details)
NEW YORK, Oct 24 (Reuters) - The U.S. Food and Drug
Administration is investigating whether the popular heartburn
drug Zantac causes carcinogens to form in the bodies of users,
in an effort to fully understand the risks posed by the already
recalled drug, the agency's spokesman said on Thursday.
The issue of whether ranitidine, commonly known as Zantac,
causes levels of the probable carcinogen N-nitrosodimethylamine
(NDMA) to rise in users' bodies has been raised previously by
Valisure, an online pharmacy that originally flagged the
potential contamination of ranitidine to the FDA.
Zantac, sold over-the-counter in the United States by French
drugmaker Sanofi SA <SASY.PA, and some of its generic versions,
have been recalled due to possible NDMA contamination of pills
that had not yet been consumed. The FDA said earlier this month
it found unacceptable levels of NDMA in drugs containing
ranitidine.
But FDA spokesman Jeremy Kahn said the regulator is now
"working to understand what happens to NDMA levels in the body,
after ranitidine has been exposed to acid in the stomach."
Zantac has been on the market for more than 35 years and was
originally sold by Glaxo Holdings Ltd, now a part of
GlaxoSmithKline PLC. At one point it was the top-selling
drug in the world.
Representatives of GSK and Sanofi were not immediately
available for comment.
(Reporting by Michael Erman; Editing by Chris Reese and Dan
Grebler)