In recent years, a lot of popular drugs, including diabetic, hypertension, and heartburn drugs, have been found to be contaminated with a carcinogen: nitrosamine.
What Drugs Have Been Recalled Due to Nitrosamine Impurities?
Since 2018, several drugs have been recalled due to containing nitrosamines. Medications that have a recall history due to nitrosamine impurities include:
- valsartan
- losartan
- irbesartan
- nizatidine
- Accuretic (quinapril HCl/hydrochlorothiazide)
- Accupril (quinapril)
- generic quinapril/hydrochlorothiazide tablets
- Zantac (ranitidine)
- Chantix (varenicline)
- metformin
- rifampin
How Does Nitrosamine Contamination in Drugs Happen?
Nitrosamines form when a secondary or tertiary amine reacts with nitrous acid. In sartan compounds, most sartans contain a tetrazole ring. This ring requires the use of sodium nitrite. Because the chemicals used to make this ring are amines or contain traces of amines, they result in the formation of nitrosamine compounds. Unlike in sartan medications, like in the case of Zantac, the origins of nitrosamine contamination are still unclear.
Other factors that contribute to nitrosamine impurities in pharmaceuticals include using nitrosating agents during production, the presence of reactive elements in starting materials, using acidic manufacturing processes, the presence of nitrosamine precursors in raw materials, and product contact with nitrogen oxides during storage.
What Should We Do to Reduce Risk of Nitrosamine Exposure?
In formulating pharmaceutical products, the FDA recommends adding antioxidant compounds such as vitamin C and vitamin E as nitrosamine-formation inhibitors. One study demonstrated that these compounds showed over 80 percent effectiveness in inhibiting nitrosamine formation.
Another approach is increasing the pH of the environment in which the pharmaceutical is made. This prevents the formation of nitrous acid, which is needed to create nitrosamine.
The justification for this decision by the FDA was that patients dependent on Januvia could be in danger if they stopped taking the medication without consulting their physician.