Pfizer has recalled four more lots of the smoking cessation drug varenicline (Chantix), according to an update on the US Food and Drug Administration (FDA) website.

In a new FDA MedWatch, the agency notes that these 0.5 mg/1 mg tablets are being recalled because of the presence of N-nitroso-varenicline, a nitrosamine impurity, at a level higher than Pfizer’s acceptable intake limit.

On July 2, the FDA reported that Pfizer had voluntarily recalled nine lots of the drug for this reason. As reported by Medscape Medical News, the company added three more lots to the recall a few weeks later. The new recall now brings to 16 the number of lots that have been recalled.

In the update, the FDA noted that although long-term ingestion of the impurity “may be associated with a theoretical potential increased cancer risk in humans,” there is no immediate risk in taking this medication. The agency added that no related adverse events (AEs) have been reported.

The four additional lots included in the newest recall are as follows:

• 00018522 (expiration date: August 2021)

• 00018523 (expiration date: August 2021)

• 00018739 (expiration date: August 2021)

• 00018740 (expiration date: August 2021)

The recalled lots were distributed in the United States and Puerto Rico from June 2019 to June 2021.

As before, the FDA noted that the benefits of stopping smoking “outweigh the theoretical potential cancer risk” from varenicline’s impurity.

It added that although the impurities may increase risk for cancer if a high level of exposure continues over a long period, the drug is intended as a short-term treatment to aid in smoking cessation.

For now, clinicians should report any AEs from varenicline to the FDA’s MedWatch program, and patients taking this treatment should consult with their healthcare practitioner or pharmacy, the update notes.

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