Chantix is a brand of varenicline, a selective alpha4-beta2 neuronal nicotinic acetylcholine receptor partial agonist approved as an aid to smoking cessation therapy. To increase your chance of success, Chantix is used with a stop-smoking program that includes education, support, and counseling. Quitting smoking lowers your risk of heart and lung disease, as well as cancer. Chantix works by blocking nicotine’s effects in the brain that make you want to smoke.
Chantix was originally approved in 2006 for use in adults as an aid to smoking cessation treatment, and safety and efficacy in pediatric patients had not been established at that time. Chantix help to reduce craving and withdrawal symptoms that happen while you give up smoking. Chantix does contain nicotine and it is not addictive.
A 2013 Cochrane overview and network meta-analysis concluded that Chantix is the most effective medication for tobacco cessation and that smokers were nearly three times more likely to quit tobacco use while on Chantix than with placebo treatment. Chantix was more efficacious than bupropion or NRT and as effective as combination NRT for tobacco smoking cessation.
Why Was Chantix Taken Off The Market?
Chantix was taken off the market in June 2021, after Pfizer, the pharmaceutical manufacturer of the drug discovered unacceptable levels of nitrosamines in batches of Chantix during production. The amount of the contaminant present was higher than what’s acceptable according to FDA guidelines. Because of this, Pfizer stopped producing the drug and distribution of Chantix worldwide.
Nitrosamines are considered to be strong carcinogens that may produce cancer in diverse organs and tissues including the lung, brain, liver, kidney, bladder, stomach, esophagus, and nasal sinus. Exposure to high concentrations of nitrosamines is associated with increased mortality from cancers of the esophagus, oral cavity, and pharynx, but not with increased mortality from cancers of the stomach or lung.
To help alleviate the medication shortage this recall could cause, the FDA is currently allowing distributors to import varenicline (generic Chantix) from Canada. In August, the FDA also approved a generic varenicline to be produced in the U.S. While these options may still contain nitrosamines, their levels are within acceptable FDA limits.
As a result, FDA alerted patients and health care professionals about Pfizer’s voluntary recall which was expanded to include all lots of varenicline (Chantix) 0.5 mg and 1 mg tablets. It also moved to reduce the impact of the drug shortage on individuals willing to quit smoking. Part of the FDA statement read “ To lessen the impact to patients from a drug shortage due to this ongoing recall, FDA will not object to certain manufacturers distributing varenicline tablets containing N-nitroso-varenicline above FDA’s acceptable intake limit of 37 ng per day but below the interim acceptable intake limit of 185 ng per day until the impurity can be eliminated or reduced to acceptable levels.
The agency has temporarily exercised regulatory flexibility and discretion with respect to Apotex’s distribution of Health Canada-approved Apo-Varenicline tablets in the U.S. containing N-nitroso-varenicline up to FDA’s interim acceptable intake limit in order to help maintain adequate varenicline supply in the U.S. for the near term.
FDA reminds patients taking recalled varenicline to continue taking their current medicine until their pharmacist provides a replacement or their doctor prescribes a different treatment. The health benefits of stopping smoking outweigh the cancer risk from the nitrosamine impurity in varenicline”, the agency concluded.
