Medicine Regulatory Authorities first became aware of the presence of the nitrosamine impurity, Nnitrosodimethylamine (NDMA), in products containing valsartan in July 2018. Valsartan is an Angiotensin II Receptor Blocker (ARB) and belongs to a family of analogue compounds commonly referred to as the sartans.Nitrosamines are chemical compounds classified as probable human carcinogens on the basis of animal studies.

Although nitrosamine impurities have been found in only some drug products, and batches of those products have been recalled when there were unacceptable levels of these impurities, nitrosamine impurities might exist in other APIs and drug products due to use of vulnerable processes and materials that may produce nitrosamine impurities.