N-Nitrosoatenolol is primarily encountered as a nitrosamine impurity in certain beta-blocker medications, particularly in atenolol-containing formulations. Its presence is of significant concern in pharmaceutical quality control due to its potential genotoxic and carcinogenic properties. As such, it is not used for any therapeutic or industrial application. Instead, its detection and quantification are critical in ensuring drug safety. Regulatory agencies require strict limits on nitrosamine impurities in pharmaceuticals, leading to the development of sensitive analytical methods like LC-MS/MS or GC-MS to monitor and control its levels in drug products. The focus is on minimizing formation during manufacturing and storage by controlling reaction conditions, avoiding nitrosating agents, and optimizing formulation stability.