Posted 13 September 2019 | By Zachary Brennan

Following its investigation into an impurity called N-nitrosodimethylamine (NDMA) in blood pressure medicines, the European Medicines Agency (EMA) on Friday said that, at the request of the European Commission, it’s beginning a review of ranitidine medicines after tests showed that some contained the impurity.NDMA is classified as a substance that could cause cancer on the basis of animal studies, although EMA explains how it is present in some foods and in water supplies but it is not expected to cause harm when ingested in very low levels.

FDA also said it's examining levels of NDMA in ranitidine and evaluating any possible risk to patients, saying it will provide more information as it becomes available.

"FDA is not calling for individuals to stop taking ranitidine at this time; however, patients taking prescription ranitidine who wish to discontinue use should talk to their health care professional about other treatment options," the agency said.

EMA’s previous review concluded that if 100,000 patients took the blood pressure medicine valsartan, manufactured by Zhejiang Huahai (where the highest levels of impurities were found) every day for six years at the highest dose, there could be 22 extra cases of cancer due to NDMA over the lifetimes of those 100,000 patients.Ranitidine medicines (more commonly known in the US as the over-the-counter drug Zantac) are used widely to reduce the production of stomach acid in patients with conditions such as heartburn and stomach ulcers, EMA and FDA explained.EMA also said that it is currently working on guidance for avoiding nitrosamines in other classes of medicines. “EMA will continue to cooperate with national authorities, EDQM and international partners to protect patients and ensure that effective measures are taken to prevent these impurities from being present in medicines,” the agency said.In April, EMA called on companies using certain reagents to manufacture the diabetes medicine pioglitazone to test their products and check their processes to rule out the presence of nitrosamine impurities, in particular NDMA.And EMA and national authorities also said they will continue investigating the presence of impurities in the blood pressure medicines, known as angiotensin II receptor blockers (ARBs), including NDMA and other impurities such as N-nitrosoethylisopropylamine (EIPNA), N-nitrosodiisopropylamine (DIPNA) and N-Nitroso-N-methyl-4-aminobutyric acid (NMBA).FDA also has recommended numerous ARB recalls as it discovered unacceptable levels of nitrosamines.Editor's note: Updated with information from FDA.