Easing Patient Fears - Recalls due to Impurities

Easing Patient Fears - Recalls due to Impurities
Hayley Kytta, PharmD, Allina Health

In recent years, there have been several high-profile recalls of drugs due to nitrosamine impurities. Nitrosamines are often formed as unintentional by-products during food processing. They are commonly found in processed meats, alcoholic beverages, and tobacco smoke. Trace amounts have also been identified in drinking water and some cosmetics. Several studies have concluded that prolonged exposure to high levels of some nitrosamine compounds can cause cancer in rats. Due to this, nitrosamines have been classified as probable or possible carcinogens in humans.

Recalls of ranitidine and metformin due to nitrosamine impurities in 2019 and 2020 caused much confusion for the public and prompted reckless headlines such as “Does Metformin Give You Cancer?”. A similar response occurred after the latest recall of varenicline (Chantix®). It is imperative that pharmacists are prepared to discuss these recalls with patients and provide insight about the reason behind the uptick in recalls. First and foremost, it is important to help patients understand that these recalls are related to impurities, rather than the medication itself. The Food and Drug Administration has found that the source of nitrosamines can be related to the drug’s manufacturing process, its chemical structure, or storage conditions. The increased prevalence of nitrosamines in pharmaceuticals is thought to be largely due to advancements in the technology used to detect such compounds. Additionally, pharmacists can help provide context around the relative risk of these impurities. After Pfizer announced the voluntary recall of varenicline due to the presence of N-nitroso-varenicline, the FDA released a statement saying that there were no urgent risks to the patients taking the medication and that there had been no reports of adverse events related to the recall. Patients may have concerns about continuing on a medication that was impacted by a recall, even if they received a lot number that was not affected. With the current Chantix® recall, pointing out the nitrosamine content of cigarettes (up to 1,760 ng/cigarette vs. 4 to 460 ng/tablet of varenicline) could be a useful point to bring up when discussing risks and benefits of continuing therapy.

References:

  1. Chan C. Why are numerous drugs being recalled due to cancer-causing contaminants? Pharmacy Today. 2021; 27(10): 19. https://www.pharmacytoday.org/article/S1042-0991(21)00723-4/fulltext. Published October 1, 2021. Accessed November 10, 2021.
  2. FDA updates and press announcements on nitrosamine in varenicline. U.S. Food and Drug Administration. https://www.fda.gov/drugs/drug-safety-and-availability/fda-updates-and-p.... Published September 17, 2021. Accessed November 10, 2021.
  3. Edwards SH, Rossiter LM, Taylor KM, et al. Tobacco-specific nitrosamines in the tobacco and mainstream smoke of U.S. commercial cigarettes. Chem Res Toxicol. 2017;30(2):540-551. doi:10.1021/acs.chemrestox.6b00268. Published December 21, 2016. Accessed November 10, 2021.
  4. Laboratory analysis of varenicline products. U.S. Food and Drug Administration. https://www.fda.gov/drugs/drug-safety-and-availability/laboratory-analys.... Published August 23, 2021. Accessed November 10, 2021.