(CNN)CVS Pharmacy has stopped selling Zantac, as well as its generic version of the heartburn medication, over concerns that they might contain a substance that could cause cancer.
CVS, the largest pharmacy chain in the country, said over the weekend it was suspending sale of Zantac and other products which contain ranitidine until further notice. The US Food and Drug Administration said earlier this month that it has learned that some ranitidine — acid-reducing and heartburn medicines, including those known by the brand name Zantac — contain low levels of an impurity that could cause cancer.Zantac and its generic counterpart have not been recalled, a statement from CVS said, and the FDA has not recommended that patients stop taking ranitidine products.Customers can return productsThe nitrosamine impurity known as N-nitrosodimethylamine, or NDMA, has been classified as a probable human carcinogen based on lab tests, and this isn’t the first time that it has been detected in a common medication.Read MoreSince last year, the FDA has been investigating NDMA and other impurities in blood pressure and heart failure medicines known as angiotensin receptor blockers or ARBs. Numerous recalls have been launched as the FDA found “unacceptable levels” of nitrosamines in several of those common drugs containing valsartan.A study published last year in the medical journal BMJ found no “markedly increased short term overall risk of cancer” among users of the valsartan drugs contaminated with NDMA. Yet that study also noted that research into long-term cancer risk is needed.Customers who have already bought the products can return them to CVS for a refund, CVS said.