How did Zantac become a potential cancer risk? FDA wants to find out

The stomach-acid-blocking drug Zantac was prescribed more than 15 million times a year with little worry about the safety of the medication, available for decades.

But it’s been harder to get the drug since September, when the Food and Drug Administration said testing showed versions of Zantac and its generic, ranitidine, contained a probable carcinogen. The French drugmaker Sanofi recalled Zantac from drugstores and retailers’ shelves. A half-dozen generic drugmakers  pulled ranitidine from the market.

How did a drug routinely used by millions of heartburn sufferers and available with or without a prescription become a potential cancer risk? It’s a question the FDA, drug manufacturers and consumers want answered.

“Every patient who comes into my office now, it’s almost the first thing that comes out in conversation: ‘What about ranitidine? What should I do with the medication? Should I come off of it or not?’ ” said Jon Ernstoff, a gastroenterologist in Meriden, Connecticut.

In September, the FDA found unacceptable levels of the probable carcinogen, NDMA, or nitrosodimethylamine, in Zantac and generic medications. The regulatory agency wants manufacturers to test and recall the drugs if NDMA levels exceed its standards. The FDA extended the voluntary recall to a similar drug, nizatidine, sold under the brand name Axid, if testing shows NDMA exceeding daily limits.

The FDA said consumers might want to choose different medications. The agency tested samples of over-the-counter alternatives such as Pepcid, Tagamet, Nexium,  Prevacid and Prilosec and found no NDMA.

 The agency’s investigation of ranitidine seeks to uncover the root cause of NDMA found in the commonly used medication. Researchers at Memorial Sloan Kettering Cancer Center in New York are assessing whether people who used Zantac or its generics face a greater cancer risk.