Anti-anxiety drug
Representational picture of medicines. Pixabay

Several countries, including Canada and Singapore, have been recalling some ranitidine drugs – approved for relieving heartburn linked with acid indigestion and sour stomach -- following a report of the presence of N-nitrosodimethylamine (NDMA), a probable human carcinogen, above acceptable levels.

The Health Canada in a statement informed that it was assessing the presence of levels of NDMA, which can increase the risk of cancer in case of long-term exposure to levels above what is considered safe, and collaborating with other regulators, including the US Food and Drug Administration and the European Medicines Agency, as well as, other Canadian companies to determine whether the drug could pose a risk to human health.

According to the agency, we are exposed to low levels of NDMA in foods such as meats, dairy products, and vegetables, as well as, in drinking water, but it is being assessed whether the commonly used drug presented a risk.

Ranitidine – an over-the-counter drug sold under various brand names, including Zantac, and as generics – is widely used across the world to reduce stomach acid and treat various conditions such as heartburn, stomach and intestine ulcers, and gastroesophageal reflux disease (GERD).

The US Food and Drug Administration (FDA) earlier in a statement cautioned it was investigating since last year low levels of NDMA and other nitrosamine impurities present in Angiotensin II Receptor Blockers (ARBs).

The statement further said the agency was working with international regulators and other industry partners to determine the source of impurity in ranitidine and evaluate whether the low levels of NDMA posed a risk to patients.

The health agencies have, however, not "called for individuals to stop taking ranitidine at this time" and said they would provide further information upon availability.

Singapore health officials have, however, halted sales and supply of eight brands of ranitidine drug in a preventive measure levels of the substance exceeded the internationally accepted rate, it said.

The FDA had last year recalled numerous blood pressure medications and ARBs after it found "unacceptable levels" of the chemical compound in those common drugs containing valsartan.

The current probe comes after Valisure, an online pharmacy company, filed a petition with FDA asking it to recall and suspend sales of ranitidine.

"Every manufacturer and every type of Zantac or ranitidine we've analyzed seems to have the same problem of the drug itself being very unstable and degrading," CNBC quoted Valisure CEO David Light as saying.

Sanofi, a Zantac manufacturing company, in a statement, said it "takes patient safety seriously, and committed to working with the FDA".

"Zantac has been around for over a decade and meets all the specified safety requirements for use in the OTC market," the statement added.

Other H2-receptor blockers that work as an alternative to ranitidine include nizatidine, famotidine, and cimetidine.