Eight brands of heartburn medicine taken off shelves due to cancer-causing impurities
Eight brands of medicine used to treat heartburn, including the widely used Zantac, have been taken off hospital, clinic and pharmacy shelves here since Monday.
This is after the Health Sciences Authority (HSA) found unacceptable amounts of an impurity in the medicines that, when taken over long periods, could cause cancer.
In an update on its website, HSA said it tested all locally marketed brands of ranitidine, which is used to reduce the production of stomach acid.
It found that eight contained trace amounts of a nitrosamine impurity, N-nitrosodimethylamine, which exceeded the internationally acceptable level.
The brands are: Zantac, Aciloc, Apo-Ranitidine, Hyzan, Neoceptin R, Vesyca, Xanidine and Zynol.
HSA said ranitidine is generally prescribed for a few days to a few weeks, and used only when necessary, while the potential risks with nitrosamines are associated with long-term exposure.
But it has stopped the sale and supply of the affected brands as a precautionary measure. It is not recalling the affected medicines from patients.
Those who have been prescribed the affected brands for short-term use may continue with their medicines.
They can speak to their doctor or pharmacist if they have any concerns.
HSA said there are sufficient treatment alternatives, like famotidine and cimetidine in the same class of medicines, as well as those in other classes like omeprazole.
According to a Bloomberg report, regulators in the US and Europe have also begun investigating the discovery of nitrosamines in generic versions of Zantac.
Some versions were recalled in Europe and Canada, and Novartis' Sandoz, one of several generic drugmakers that distribute Zantac, is halting worldwide distribution.
In Singapore, GlaxoSmithKline is the local supplier of the brand.
Nitrosamine impurities have recently been found to have formed unexpectedly during the manufacture of some medicines, HSA said.
In March, it pulled three brands of a major high blood pressure drug, losartan, after finding similar impurities. The brands - Hyperten, Losagen and Losartas - were taken by about 137,000 people here.