In mid-September, the Food and Drug Administration warned that a popular heartburn drug, commonly known by the brand name Zantac, could contain small amounts of a cancer-causing chemical. Over the weekend, the chain pharmacy CVS announced it would stop selling all versions of the drug, a move that follows a voluntary recall of the drug from several other chains, including Walmart. [Update: On Monday, Walgreens announced it would stop selling Zantac and related drugs as well.]
The troublesome chemical is called N-nitrosodimethylamine, or NDMA. NDMA is routinely used to induce cancer in lab animals, and it’s thought to be a probable human carcinogen as well. Like most other carcinogens, you would probably need to be exposed to NDMA for a long time for your cancer risk to noticeably increase. In high doses, though, it can also be an acutely fatal poison.
The FDA isn’t worried about a mass NDMA poisoning, but on September 13, the agency warned that testing has detected low levels of NDMA in samples of the heartburn drug ranitidine, which is both sold over-the-counter and via prescription. A little over a week later, the pharmaceutical company Sandoz announced a recall of its prescription ranitidine drugs; a day after that, Apotex Corp announced a similar recall of its OTC version, pulling it from Walmart, Walgreens, and Rite Aid stores.
On Saturday, CVS announced it would temporarily suspend sales of all ranitidine products, both Zantac and any generic brands, “in an abundance of caution” prompted by the FDA advisory. Though this suspension isn’t a recall, the company added that any customers who bought these products could return them to CVS for a refund.
To be clear, the FDA isn’t claiming that anyone is in danger. NDMA is regularly found in the environment, so trace amounts of it often end up in our food and water. And as of now, the agency’s preliminary testing has found that the NDMA levels in these samples “barely exceed amounts you might expect to find in common foods.”
That said, it’s understandable why people are on guard. Just last year, some supplies of another drug—the blood-pressure lowering medication valsartan—were found to be contaminated with unsafe levels of NDMA, prompting a widescale series of recalls. In that case, the contamination was traced back to changes in the manufacturing process used by certain companies in China.
As scary as the word “carcinogenic” might sound, though, it’s worth putting things in perspective. A study last year, for instance, found that no one experienced an increased risk of cancer from taking valsartan drugs tainted with NDMA, at least in the short term. And the potential cancer risk posed by taking Zantac might be even less this time around.
Right now, it isn’t known how NDMA might have ended up in ranitidine products, nor how widespread the contamination problem could be. We do know that under certain conditions, ranitidine itself can actually transform into NDMA. But NDMA can form in lots of different ways, so the answer may lie elsewhere.
At this point, the FDA isn’t telling people with chronic heartburn to stop taking their ranitidine. But they do note that ranitidine isn’t the only heartburn drug of its kind on the market. Those taking an OTC version can easily switch to other OTC drugs that work by blocking histamine-2 (h2), such as famotidine (Pepcid) and nizatidine (Axid). But anyone planning to stop taking prescription ranitidine should consult with their doctor first.