On September 28, CVS Pharmacy announced that it’s pulling some heartburn medications from its shelves until further notice, following an alert from the Food and Drug Administration that they may contain a cancer-causing ingredient.

CNN reports that the medication in question is ranitidine, and CVS will stop selling its store brand version and the more commonly known brand-name version Zantac. Though tests are still ongoing, the FDA has found that ranitidine contains N-nitrosodimethylamine (NDMA), which is a “probable human carcinogen,” according to a statement from CVS.

CVS’s voluntary suspension of sales is a “better safe than sorry” course of action—the FDA hasn’t issued a formal recall of Zantac/ranitidine or even suggested that users stop taking the medication. In its statement, CVS says that “the levels [of NDMA] that FDA is finding in ranitidine from preliminary tests barely exceed amounts found in common foods.” According to the Agency for Toxic Substances and Disease Registry, a division of the U.S. Department of Health and Human Services, NDMA is also found in tobacco, cured meats, beer, fish, cheese, and even the air we breathe [PDF].

Ranitidine is a type of H2 receptor blocker, which decreases heartburn and acid reflux symptoms by preventing stomach cells from releasing excess acid. It isn't the only H2 receptor blocker on the market, so this might be a good time to consult your healthcare provider or pharmacist about switching to a different one, like Pepcid (famotidine) or Tagamet (cimetidine).

The FDA said in a statement that it will continue investigating the potential risk of taking ranitidine and share its findings when available.

[h/t CNN]