Potential contamination of varenicline medicines being investigated by the TGA as batch recall begins
The Therapeutic Goods Administraion (TGA) says it is investigating potential contamination of varenicline medicines with the nitrosamine impurity, N-nitrosovarenicline.
The regulator says it “has been advised that very low levels of the N-nitrosovarenicline have been detected in Australian varenicline products”.
As a precautionary measure, Pfizer Australia, the manufacturer of Champix (varenicline) has paused global distribution of the product while this issue is investigated.
In addition, two batches have been recalled from Australian pharmacies after they were identified as containing unacceptable levels of N-nitrosovarenicline.
The recall is for Champix varenicline (as tartrate) 1.0mg tablet blister pack batches EM9960 & EM9961. (Exp: Feb 2022, AUST R 124941).
The recall notification states that it was instigated “due to the presence of a nitrosamine impurity, N-nitrosovarenicline, above Pfizer’s acceptable concentration limit in these lots of Champix.
“Nitrosamines are commonly found in low levels in a variety of foods, as well as in some drinking water. Long-term exposure, over many years, can increase an individual’s risk of developing cancer”.
“As a precautionary measure, Pfizer is pausing distribution of Champoix worldwide, pending further testing. Patients will need to consult with their healthcare professional to choose an alternative treatment option,” the notification states.
Pharmacists are advised to inspect stock and quarantine all units of Champix tablets from the impacted batches.
Upon receipt of a completed ‘Product Recall Fax Back Form’ (supplied to impacted users by Pfizer), Pfizer Trade Operations will contact customers to arrange return and credit of stock.
Patients 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.
The TGA says it is “working with varenicline sponsors to further investigate this issue and determine what actions may be required”.
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.