The Food and Drug Administration (FDA) is now confident that any newly manufactured varenicline for the US market should have levels of the N-nitroso-varenicline impurity at or below the FDA’s acceptable intake limit of 37ng per day.

Varenicline is a nicotinic receptor partial agonist indicated for use as an aid to smoking cessation treatment.

In July 2021, the FDA permitted varenicline tablets containing N-nitroso-varenicline up to the interim acceptable intake limit of 185ng per day to be distributed in the US in order to maintain an adequate supply of the smoking cessation therapy in the country. The FDA determined that exposure to N-nitroso-varenicline below 185ng per day would present minimal additional cancer risk when compared with a lifetime exposure at 37ng per day.

According to the FDA’s current assessment, manufacturers can adequately supply the market with varenicline at or below the acceptable intake limit of 37ng per day.


FDA updates and press announcements on nitrosamine in varenicline (Chantix). News release. US Food and Drug Administration. Accessed May 5, 2022.