Authorities in the EU are aware that some active substances are at a higher risk of formation of active substance derived nitrosamine impurities. 

Such active substances contain vulnerable amine functional groups that can undergo a reaction called nitrosation (often a secondary amine). Nitrosamines are thought to form when the nitrosatable amine group in the active substances and trace nitrite impurities in the inactive ingredients (excipients) react.

Active substances that contain secondary amines appear particularly vulnerable to this reaction, although some cases involving active substances with tertiary amines have also been observed.

More information on the root causes of nitrosamine impurities is available in  EMA's question-and-answer document on the Article 5(3) CHMP opinion (Question 4). 

All marketing authorisation holders for EU medicines should consider this risk factor in their risk evaluations as a matter of priority, if they have not already done so.

If a risk is confirmed, they should prioritise confirmatory testing. If testing confirms the presence of nitrosamines, companies should immediately report their findings to the relevant competent authority. 

Guidance for marketing authorisation holders on confirmatory testing is available.

This is a precautionary step to ensure early detection of any potential risk, and to enable prompt regulatory action if necessary. 

There is no immediate risk to patients who are taking these medicines. Patients who have any questions about their treatment should speak to their doctor. 

Authorities will provide updates as necessary.