Pfizer (NYSE:PFE) has stopped international shipments of the smoking-cessation drug Chantix (varenicline) after concluding it had elevated levels of a potential carcinogen.
The substance in question, nitrosamines, are organic compounds thought to cause cancer in various organisms.
“We believe the benefits of Chantix/Champix outweigh the very low potential risks, if any, posed by nitrosamine exposure on top of other common sources over a lifetime,” said Pfizer spokesperson Steven Danehy. Champix is the brand name of Chantix outside of the U.S. “We are actively working with regulatory authorities around the world to communicate the appropriate information in accordance with specific actions and timing, which vary by country.”
Pfizer suspended distribution as a precaution. The company is also researching to determine whether additional lots of the drug contain nitrosamines.
Earlier this month, health officials in Canada announced a recall of the drug…