Nitrosamines are chemical compounds classified as probable human carcinogens on the basis of animal studies. EU regulators first became aware of nitrosamines in medicines in mid-2018 when nitrosamine impurities, including N-nitrosodimethylamine (NDMA), were detected in blood pressure medicines known as 'sartans'. There is a very low risk that nitrosamine impurities at the levels found in medicines could cause cancer in humans.