Yes, you should consider both the API and its possible degradation pathway and the intermediated in the last step of the reaction synthesis. Pay attention on structural alerts for genotoxic impurities (ICH M7). Nitrosamine compounds are reported to demonstrate genotoxic activity in several animal species and are classified as “ probably or possible human carcinogens.”

Nitrosamines are probable/possible human carcinogens, and therefore potential causes of nitrosamine formation during manufacture of i) APIs and ii) drug products should be considered and risk assessments carried out as appropriate.

You may find the recent FDa guidance document useful:

https://www.fda.gov/media/141720/download#:~:text=Formation%20of%20nitrosamines%20is%20possible,23%20under%20acidic%20reaction%20conditions.&text=In%20general%2C%20processes%20that%20use,risk%20of%20generating%20nitrosamine%20impurities.