After discovering some batches could be contaminated with a carcinogen, Pfizer has halted the distribution of its stop-smoking drug Chantix.
During testing, Pfizer found high levels of N-nitrosodimethylamine (NDMA) – a common nitrosamine – in some batches of Chantix pills.
These tests were part of enhanced monitoring efforts from international drug regulators, which require manufacturers to test for any possible impurities in their products.
Pfizer has suspended distribution and will carry out further testing. The company will also be recalling some batches that contain high levels of NDMA.
The FDA hasn’t issued a recall on this product. However, health authorities in some other countries, including Canada, have recalled the drug until further tests have been carried out.
Nitrosamines are commonly found in the environment, usually at low levels. But, scientists believe that exposure at high levels can pose a cancer risk.
What is Chantix?
Varenicline, which is marketed by Pfizer as Chantix, is a popular anti-smoking drug that was initially approved by FDA in 2006.
According to the Chantix website, it’s a three-to-six-month treatment that helps people overcome the need to smoke tobacco and has been prescribed to over 13 million people.
It’s suitable for adults over 18 that are struggling to quit smoking and is used for 12 to 24 weeks. Chantix sales were $919 million in 2020 and $1.1 billion in 2019.
Some other health concerns have been raised about Chantix, including mental health side effects like anxiety, depression, and even suicidal thoughts.
What happens next?
Pfizer says its currently working with regulators and will communicate publicly, as per the guidance from regulatory authorities.
A Pfizer spokesman said the company believes the risks are low and are outweighed by the drug’s benefits. They added that this pause was ordered out of an abundance of caution.
People who are currently using Chantix should contact their health care provider for guidance on the best way to proceed going forward.