Since the outset of our discovery of impurities called nitrosamines in some types of drugs more than two years ago, the U.S. Food and Drug Administration has undertaken a thorough investigation in an effort to protect patients. While nitrosamines are common in water and foods, nitrosamine impurities may increase the risk of cancer if people are exposed to them above acceptable levels and over long periods of time. For this reason, the discovery of unexpected nitrosamine impurities in some drug products is a serious concern, and the FDA has been working, in collaboration with regulatory counterparts around the world, to find and remove drugs with unacceptable nitrosamine impurities from the U.S. drug supply. As we do so, we’re also taking proactive efforts to help ensure that in the future, drugs can be free from unsafe levels of these impurities from the start of production.

Ensuring that drugs are safe, effective and high-quality is a critical part of FDA’s mission. In our continued efforts to be transparent and provide guidance to manufacturers on how to detect and prevent unacceptable levels of nitrosamine impurities, today we’re publishing our guidance Control of Nitrosamine Impurities in Human Drugs for immediate implementation. This guidance recommends steps, including a comprehensive risk assessment strategy and other actions that manufacturers can take to reduce or prevent the presence of nitrosamine impurities in their drugs.

There are many reasons why these impurities might appear in some drugs, and consequently many approaches to screening for and preventing the appearance of nitrosamines to help ensure drug quality and safety. The source of these impurities can be related to the drug’s manufacturing process, the materials used in manufacturing, the drugs’ chemical structure, or even the conditions in which drugs are stored or packaged. Under FDA’s oversight, manufacturers are responsible for mitigating these impurities.

The most common nitrosamine impurity, N-nitrosodimethylamine (NDMA), is found at low levels in water and foods, including cured and grilled meats, dairy products and vegetables. The FDA and the international scientific community do not expect NDMA to cause harm when ingested at low levels. However, given the risk that genotoxic substances such as NDMA may increase the risk of cancer if people are exposed to them above certain levels and over long periods of time, manufacturers have recalled drugs with NDMA levels higher than the FDA’s recommended acceptable intake levels. Patients taking medications with potential nitrosamine impurities should not stop taking their medications and should talk with their health care professional about concerns and other treatment options.

We believe that the guidance we’ve issued today will assist manufacturers in preventing unacceptable levels of nitrosamines in drugs. Protecting patients is the FDA’s highest priority, and we will continue to work with manufacturers and our international regulatory partners to investigate and definitively resolve this problem.

Posted on the FDA website on 1 September 2020