New Delhi: The US Food and Drug Administration late Friday downplayed the risk associated with popular antacid medicine ranitidine, saying that the carcinogen N-nitrosodimethylamine (NDMA) is not formed after ingestion of the drug and that levels of the contaminant in most samples were similar to those found in common foods.
“The agency has tested numerous ranitidine products on the market over the past few months, and today we’re releasing a summary of the results we have to date. Through our testing so far, we have found levels of NDMA in ranitidine that are similar to the levels you would expect to be exposed to if you ate common foods like grilled or smoked meats," Janet Woodcock, director at the regulator’s Center for Drug Evaluation and Research, said in a statement.
However, Woodcock also pointed out that while most samples had NDMA at levels “much lower" than what third-party scientists first claimed, its presence in some samples did exceed acceptable amount.
The US FDA considers 96 nanograms per day, or 0.32 parts per million, as the acceptable limit for ranitidine, and has asked pharmaceutical companies to voluntarily recall ranitidine products if the contaminant breaches the limit in their products.
The US regulator has also asked manufacturers of another antacid nizatidine, popularly sold under the brand Axid, to test their products for presence of NDMA and initiate a voluntarily recall if they find the carcinogen above acceptable daily intake level. Nizatadine is is chemically similar to ranitidine.
The regulator is still working with manufacturers to investigate the true source of NDMA and to understand the root cause of the low levels of NDMA present in the drugs, it said.
Meanwhile, it has advised doctors and patients to consider using other products instead of rantidine, like Pepcid, Tagamet, Nexium, Prevacid and Prilosec, and their generics. Tests of these products have shown show no NDMA impurities.
The US FDA had last month issued a safety alert citing traces of NDMA, a known carcinogen, in ranitidine.
Following the US regulator’s safety alert, the Drug Controller General of India also issued a directive to all state regulators asking them to get manufacturers to test anti-acidity drug ranitidine for the impurity. Many other drug regulators world over have also issued similar advisories and are conducting tests.
Dr Reddy’s Laboratories had also initiated a voluntary recall of the medicine at the retail level in the US on 1 October after the US FDA’s caution note.
On 25 September, GlaxoSmithKline Pharmaceuticals Ltd suspended the distribution and supply of ranitidine hydrochloride products to all markets, including India, as a precautionary measure after regulatory authorities detected the carcinogen in its products.
The move by GSK came after the European Directorate for the Quality of Medicines (EDQM) suspended the certificate of suitability of its bulk drug supplier Saraca Laboratories Ltd.
In India, GSK Pharma manufactures the drug under Zinetac. Other brands are JB Chemicals and Pharmaceuticals Ltd’s Rantac, Sun Pharmaceuticals Ltd's Histac, Torrent Pharmaceuticals Ltd's Ranitin, Ajanta Pharma Ltd's Pepitran. Dr Reddy’s does not sell rantidine products in India.