Published Sep 16, 2021
Pfizer is recalling all of its stop-smoking drug Chantix due to high levels of a cancer-causing chemical.
This comes after multiple recalls on both the wholesale and consumer level for specific lots of the drug, which contains high levels of a nitrosamine, N-nitroso-varenicline.
In a statement obtained by SurvivorNet, Pfizer said it was now taking this step because “alternative suppliers [of similar drugs] have been approved in the United States.”
The recall got underway in June when the Food and Drug Administration released the results of testing, which found levels of the carcinogen N-nitroso-varenicline that exceeded the amount at which consumption becomes a cancer risk.
Consumers can return any product for reimbursement, Pfizer says in its release, which also notes: “Wholesalers and Distributors with an existing inventory of Chantix tablets, should stop use and distribution and quarantine the product immediately.”
Those taking the drug are encouraged to speak with their healthcare provider about alternative treatment options.
The FDA had previously released information about the risk of N-nitroso-varenicline.
“N-nitroso-varenicline may increase the risk of cancer if people are exposed to it above the acceptable intake limit and over a long period of time, but a person taking a drug that contains N-nitroso-varenicline at-or-below the acceptable intake limit every day for 70 years is not expected to have an increased risk of cancer,” explained the FDA.
“Agency scientists evaluated the risk of exposure to N-nitroso-varenicline at interim acceptable intake levels up to 185 ng per day (92.5 ppm) and determined that it presents minimal additional cancer risk when compared to a lifetime of exposure to N-nitroso-varenicline at the 37 ng per day (18.5 ppm) level.”
The levels of N-nitroso-varenicline found in Chantix ranged from 155 to 474 ppm, far exceeding those acceptable intake levels.
The FDA approved Chantix in May 2006 to help adults age 18 and over quit smoking, which remains the number one risk factor for developing lung cancer. The medication is typically used for 12 to 24 weeks.
In June 2020, the FDA asked companies to recall the popular diabetes drug metformin due to an apparent cancer risk. The agency said that it found a high level of NDMA in several batches of the extended-release form of the drug, which is often prescribed to control high blood sugar in patients with type 2 diabetes. NDMA contamination was also responsible for the recall of heartburn drug Zantac sold by Sanofi SA in 2019.
The Food and Drug Administration issued guidance in September 2000 that notified all drug makers of the agency’s plan to monitor nitrosamine levels in products.
The term nitrosamine refers to the class of compounds whose chemical compounds are constructed by a nitroso group bonded to an amine. The cancer-causing impurities start to show up when a nitrosamine reaction occurs between those amines.
In its initial report, the FDA identified seven different nitrosamine impurities, including NDMA. It also explained that these impurities are often created during the production of a drug and had not been purposely put into any medication to the agency’s knowledge.
Because nitrosamines are probable or possible human carcinogens, the FDA now recommends that manufacturers consider the potential causes of nitrosamine formation during product production. Manufacturers are also tasked with evaluating the risk and testing for nitrosamine contamination or formation in their APIs and drug products.
Nitrosamines are most commonly found in cigarettes and cured meats.