Consumers and health professionals are advised that the TGA is investigating potential contamination of varenicline medicines with the nitrosamine impurity, N-nitrosovarenicline.
Varenicline, marketed in Australia as Champix, is a prescription medicine that assists adults to stop smoking by helping to reduce nicotine cravings and withdrawal symptoms. Smoking is associated with serious health problems that can lead to death.
The TGA has been advised that very low levels of the N-nitrosovarenicline have been detected in Australian varenicline products.
As a precautionary measure, the sponsor of Champix, Pfizer Australia, has paused global distribution of this product while this issue is investigated. In addition, two batches have been recalled from pharmacies that were identified as containing unacceptable levels of N-nitrosovarenicline. Details of this recall can be found in the TGA's System for Australian Recall Actions database.
Pfizer Australia has notified the TGA of the shortage of Champix tablets. Information about the shortage is published on the Medicine Shortage Reports Database.
Consumers are advised to continue to take their varenicline medicines as prescribed. Patients should not stop taking their varenicline medicines unless instructed to by their health professional.
What is N-nitrosovarenicline?
N-Nitrosovarenicline is a type of nitrosamine that is present as an impurity. Nitrosamines are commonly found in low levels in a variety of foods, particularly smoked and cured meats, as well as in some drinking water and in air pollution. Long-term exposure, over many years, can increase an individual's risk of developing cancer.
The additional risk that would be posed by potential trace levels of N-nitrosovarenicline in varenicline medicines is considered to be very low. There are no data available to directly evaluate the carcinogenic potential of N-nitrosovarenicline.
The TGA began investigating nitrosamine impurities that have been found in 'sartan' blood pressure medicines in late 2018, and in metformin products and ranitidine products in late 2019.
What should consumers do?
Please be aware that it has been confirmed that N-nitrosovarenicline is present at low levels in varenicline products supplied in Australia.
If you take varenicline, do not stop your treatment without first consulting a doctor or pharmacist. It is important you seek advice from your doctor if you are unable to access your full course of Champix due to the current medicine shortage.
If you have any other questions or concerns regarding this issue, speak to your health professional.
What should health professionals do?
Please be aware of this potential issue and advise patients accordingly. It has been confirmed that N-nitrosovarenicline is present at very low levels in varenicline products supplied in Australia.
Health professionals should be aware that there may be limited availability of this product due to the current shortage. Alternative treatment options should be considered while varenicline is unavailable.
You may wish to remind patients to keep taking their medicines as normal, in line with the instructions in the Product Information and reassure them that that the risks posed by N-nitrosovarenicline at the trace levels observed overseas are considered very low.
What is the TGA doing?
The TGA is working with varenicline sponsors to further investigate this issue and determine what actions may be required.
The TGA has reviewed results reported by sponsors of varenicline medicines on the ARTG.
Sponsors of affected medicines are taking corrective action to introduce impurity control measures to ensure that only batches of varenicline that comply with internationally acceptable intake limits are released.
The TGA and other international regulators will continue to monitor medicines to ensure that they meet appropriate quality standards.