Pfizer has announced that it has suspended the global distribution of Chantix after the drug was tested for impurities, making it difficult for smokers who want to buy the drug to quit smoking, according to Fierce Pharma.

The company halted the distribution of the popular smoking cessation aid after it found unacceptable levels of potentially carcinogenic substances called nitrosamines in certain lots of Chantix.

A spokesman for Pfizer said the company believes Chantix’s benefits “outweigh the very low potential risks, if any, posed by nitrosamine exposure from varenicline on top of other common sources over a lifetime.”

Actively composed of varenicline, Chantix has been found effective in helping you quit smoking. The drug works by blocking nicotine’s effects in the brain that make you want to smoke, according to WebMD.

Chantix is a prescription drug that helps reduce craving for and decrease the pleasurable effects of nicotine from cigarettes or other tobacco products.

The suspension of Chantix seems to stem back to the global recalls of metformin, valsartan, and ranitidine in recent years, as they were also found to be tainted with potential carcinogens.

Pfizer’s internal testing showed unacceptable levels of nitrosamines in some Chantix lots, prompting the company to stop the global distribution of the smoking cessation aid.

The spokesman said, “We have worked hand-in-hand with regulatory authorities around the world who are taking varying approaches and have varying timelines. All information has been communicated publicly per guidance from regulatory authorities.”

Pfizer’s Korea unit informed all distributors that certain lots of Chantix were out of stock, according to the Korea Biomedical Review – a South Korea-based online English-language newspaper.

Canadian officials have also posted a notice about the recall of the drug.

The impurities can develop during the manufacturing or storage of the drugs, according to Fierce Pharma.

Drug regulatory bodies have said that nitrosamines can be carcinogenic after long-term exposure.

Last year, Chantix generated $919 million. The FDA approved the drug in 2006, but it is now available in generic since November 2020. The article appeared on Fierce Pharma.