CVS customers who have already purchased ranitidine products can return them to CVS for a refund. The retailer will continue to sell other over-the-counter H2 Blockers like Pepcid, Tagamet, and their generic equivalents (famotidine and cimetidine). The FDA is encouraging anyone wishing to discontinue the use of ranitidine to discuss alternative treatments with their doctor.

CVS made the decision to remove these products from its shelves following a Product Alert from the U.S. Food and Drug Administration (FDA). The FDA warns that ranitidine may contain low levels of nitrosodimethylamine (NDMA), which is a probable human carcinogen.

CVS said in a statement that this decision was made “out of an abundance of caution.” Ranitidine products have not been recalled, the FDA is not recommending that patients stop taking them, and medications containing ranitidine continue to be sold at other retailers. So far, the levels of NDMA found in ranitidine products are only slightly higher than the amounts found in common foods.