GlaxoSmithKline has globally recalled its popular heartburn remedy Zantac (ranitidine), after the US Food and Drug Administration (FDA) found “unacceptable” levels of carcinogen in the medicine due to a possible contamination with N-nitrosodimethylamine (NDMA).

The federal agency released a statement alerting patients to the possible contamination, after investigating NDMA and other nitrosamine impurities in blood pressure and heart failure medicines called Angiotensin II Receptor Blockers (ARBs) since last year.

In the case of ARBs, the organisation recommended numerous recalls as it discovered unacceptable levels of nitrosamines.

The four versions being recalled are Zantac 150mg/10ml Syrup, Zantac 50mg/2ml Injection, Zantac 150mg Tablets and Zantac 300mg Tablets, all only availably by prescription.

NDMA, the chemical in question, is classified as a “probable human carcinogen”, based on results from laboratory tests. It is a known environmental contaminant found in water and foods, including meats, dairy products, and vegetables.

The Administration says that it is working with international regulators and industry partners to determine the source of the impurity in Zantac, but in the meantime has recalled the product from the shelves.