A Third Recall of the Popular Pfizer Drug
- Pfizer is recalling more of the stop-smoking drug Chantix due to the presence of known cancer-causing chemical nitrosamine.
- This comes as the Food and Drug Administration released the results of testing which found carcinogenic levels of nitrosamine that far exceeded the amount at which consumption becomes a cancer risk.
- It also comes as the FDA is putting its full support behind Pfizer’s COVID vaccine, which became the first to receive approval from the government agency.
The drug company has announced the recall of an additional four lots (16 total) at the consumer level due to the presence of nitrosamine in varenicline, which is the main component of the prescription medication.
Read More“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,” explains 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 nitrosamine found in Chantix ranged from 155 to 474 ppm, far exceeding those acceptable intake levels.
The company had previously recalled two lots of Chantix 0.5mg tablets, two lots of Chantix 1 mg tablets, and eight lots of a Chantix kit of 0.5mg/1 mg tablets at the consumer level last month due to the presence of nitrosamine.
The issue is that the amount of the nitrosamine in question, N-nitroso-varenicline, that is present in the medication is above the Pfizer-established Acceptable Daily Intake (ADI) level.
The FDA had been urging the company to issue a recall at the consumer level for some time before they finally went forward with the move last month.
It was a suggestion that the drugmaker finally agreed to, according to a release sent out by the government agency.
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.
Pfizer will continue to delay the release of varenicline in the U.S. until testing confirms that N-nitroso-varenicline levels are below what the company considers to be acceptable.
The FDA says that individuals should not stop taking Chantix without speaking to a medical professional. At the same time, the agency is recommending that health care professionals look for other options to treat patients. Any Chantix that these healthcare workers have on hand should be quarantined, the FDA says, and not provided to patients. The FDA says it is “actively considering options to help mitigate a shortage of varenicline in the U.S. including working to identify an alternate supplier.”
In June 2020, the FDA asked companies to recall the popular diabetes drug metformin due to an apparent cancer risk. The agency said that a high level of NDMA was found 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.
What is Nitrosamine?
The Food and Drug Administration issued guidance in September 2000 that notified all drug makers of the agency’s plan to start monitoring the levels of nitrosamine 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, though at levels low enough that they are not carcinogenic.
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