Taipei, July 2 (CNA) Pfizer Inc. in Taiwan is recalling some lots of its anti-smoking tablets, Champix, after elevated levels of nitrosamine impurities were found in the prescription drug, according to Taiwan's Food and Drug Administration (FDA).
FDA official Hung Kuo-teng said Friday that an estimated 600,000 Champix pills with four lot numbers (00019669, 00019012, 00019601 and 00019602) are expected to be recalled by July 22.
The decision was made after Pfizer Inc. in the United States said it found elevated levels of nitrosamines in Chantix, the name under which Champix is sold in the U.S., and Hung said the pharmaceutical company is still investigating the situation.
In a February 2021 report, the U.S. Food and Drug Administration has identified seven nitrosamine impurities that theoretically could be present in drug products, and said five of them have been detected in drug substances.
Some of them, including N-Nitrosodimethylamine (NDMA), could induce cancer in humans, and the U.S. FDA and other regulatory authorities have asked pharmaceutical companies to assess their products for the impurities, according to Bloomberg News.
In a statement issued Friday, Pfizer Taiwan said the impurities it found in varenicline (the active ingredient for Champix/Chantix) should not be mistaken for NDMA and that they were not any of the seven impurities the FDA identified in its report.
The company has yet to determine the risk to human health of the nitrosamines found in its smoking-cessation drug, but it has halted the global distribution of the pills and some recalls have begun, according to international media.
The Taiwan FDA said medical institutions and pharmacies should stop prescribing and dispensing Champix and begin returning the product, the FDA said.
People concerned about their use of the medication should immediately consult their doctors, the Taiwan FDA said.
