Novartis, the maker of a generic form of the popular heartburn drug Zantac, said Wednesday it will cease distribution of the medicine after investigations suggested that generic and branded versions contain a known carcinogen.
A distribution halt is not the same as a full recall, and it means that generic Zantac (ranitidine) remaining on store shelves can still be sold, CBS News reported.
The move stems from an announcement made last Friday by the U.S. Food and Drug Administration. In a statement, the agency said that a substance that could cause cancer had been found in some ranitidine heartburn and ulcer medicines, including the brand name drug Zantac, and the source of this contamination is being investigated.
Sanofi, the maker of Zantac, said in a statement on Wednesday that "there are currently no plans to stop distributing or manufacturing Zantac or other ranitidine products outside of Canada," and added that "we are conducting our own robust investigations to ensure we continue to meet the highest quality safety and quality standards."
While preliminary tests found low levels of the nitrosamine impurity N-nitrosodimethylamine (NDMA) in some ranitidine products, the FDA said last week that this does not mean patients taking the drugs should now stop using them.
NDMA is the same contaminant found in many brands of blood pressure and heart failure medications during the past year, leading to recalls.
Patients who are taking prescription ranitidine who want to stop using it should discuss alternatives with their health care provider, the FDA advised. Those taking over-the-counter (OTC) ranitidine could switch to other OTC heartburn medicines.
Several drugs are approved for the same or similar uses, the FDA noted.
NDMA is an environmental contaminant found in water and foods, including meats, dairy products and vegetables. It is classified as a probable human carcinogen.
"Drug impurities remain a major national concern," said Dr. David Robbins, associate chief of endoscopy at Lenox Hill Hospital in New York City. "While Zantac may prove safe in the long run, this latest statement adds confusion and concern, so my interim advice to patients is simple: switch to another drug … and of course, confirm with your doctor the need for an antacid."
The FDA said it's evaluating whether the low levels of NDMA in ranitidine pose a risk to patients and that it will post that information when it's available.
In a statement, Sanofi said that it "takes patient safety seriously, and we are committed to working with the FDA. Zantac OTC [over the counter] has been around for over a decade and meets all the specified safety requirements for use in the OTC market."
In the meantime, Dr. Janet Woodcock, director of the FDA's Center for Drug Evaluation and Research, said the FDA is working with international regulators and industry partners to find out where the contamination originated.
"The agency is examining levels of NDMA in ranitidine and evaluating any possible risk to patients," she said in a news release. "The FDA will take appropriate measures based on the results of the ongoing investigation."
Large amounts of NDMA may pose a risk, but the levels of NDMA found in ranitidine in preliminary tests barely exceed amounts found in common foods, according to the FDA.
Ranitidine decreases the amount of acid created by the stomach. OTC ranitidine is approved to prevent and relieve heartburn, and prescription ranitidine is approved for a number of uses, including treatment and prevention of ulcers of the stomach and intestines, and treatment of gastroesophageal reflux disease (GERD).
Similar contamination in heart medicines is also under investigation.
"The FDA has been investigating NDMA and other nitrosamine impurities in blood pressure and heart failure medicines called Angiotensin II Receptor Blockers [ARBs] since last year," Woodcock said. "In the case of ARBs, the FDA has recommended numerous recalls as it discovered unacceptable levels of nitrosamines."
The U.S. Agency for Toxic Substances & Disease Registry has more on NDMA.