Pfizer is voluntarily recalling an additional four lots of its smoking-cessation product, Chantix (varenicline) (0.5 mg/1 mg tablets) to the patient (consumer/user) due to the presence of a nitrosamine impurity, N-nitroso-varenicline, potential carcinogen, above Pfizer’s established acceptable daily intake level.

Last month (July 2021), Pfizer recalled 12 lots of Chantix: two lots of Chantix 0.5-mg tablets, two lots of Chantix 1-mg tablets, and eight lots of a Chantix kit of 0.5-mg/1-mg tablets due to the N-nitroso-varenicline impurity.

To date (as reported on August 16, 2021), Pfizer reported that it had not received any reports of adverse events that have been related to this recall. The product lots were distributed nationwide to wholesalers and distributors in the US and Puerto Rico from June 2019 to June 2021.

This marks the latest product in the industry over past three years to be recalled or investigate for possible nitrosamine impurities, N-nitrosodimethylamine (NDMA), a potential carcinogen.

In 2018, the US Food and Drug Administration and the European Medicines Agency initiated investigations of nitrosamine impurities in certain “sartan”-containing APIs, used in anti-hypertensive and cardiovascular drugs, such as valsartan candesartan, irbesartan, losartan, and olmesartan. They later broadened those investigations into prescription and over-the-counter forms of ranitidine, a H2 (histamine-2) blocker used to decrease the amount of acid created by the stomach, and later metformin extended-release products. As part of their investigations, the regulatory agencies issued guidelines for testing of products to detect nitrosamine impurities, acceptable daily intake levels, and risk evaluation and risk assessment.

Source: US Food and Drug Administration