The manufacturer of Zantac has issued a recall in the U.S. and Canada amid growing concerns over potential carcinogens lurking in the popular heartburn drug.
Pharmaceutical company Sanofi announced the voluntary action on Friday, calling it a “precautionary measure” following Food and Drug Administration tests that revealed traces of a possibly cancer-causing chemical, N-nitrosodimethylamine, or NDMA, in medicine used to relieve common ailments like indigestion and ulcers.
In its statement, Sanoifi cited “inconsistencies in preliminary test results” of Zantac’s active ingredient, ranitidine.
The FDA raised concerns over its findings in a notice last month, though it did not call for the public to toss out the medication.
Sanofi said it is still evaluating both the active ingredient and the finished product.
In the meantime, the FDA has noted that anyone taking the over-the-counter drug can consider a range of alternatives. Proton pump inhibitors such as Prevacid, Prilosec and Nexium, none of which have ranitidine, are not included in the FDA’s warning and may be effective substitutes.
This article originally appeared on HuffPost.