US retailer CVS has become the latest to suspend the sale of a heartburn drug being investigated for links to cancer.
It follows concern in several countries over the presence of impurities in Zantac and other ranitidine products.
Canada and France have already announced Zantac recalls. The US and the European Union are investigating.
Health authorities say there is no immediate risk, but patients have been advised to consult a doctor who can prescribe alternatives to ranitidine.
What is the fear about?
On 13 September, both the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) published their decisions to review the presence of N-nitrosodimethylamine (NDMA) in medicines containing the drug ranitidine.
NDMA is found in water and foods, including meats, dairy products, and vegetables, but is not expected to cause harm when ingested in very low levels, EMA says.
Ranitidine products are used to reduce the production of stomach acid in patients with conditions such as heartburn and stomach ulcers.
They are available over-the-counter and on prescription.
Who has recalled the products so far?
CVS’s announcement on Saturday said it was suspending the sale of Zantac and CVS Health brand ranitidine products “out of an abundance of caution“.
“Zantac brand products and CVS brand ranitidine products have not been recalled, and the FDA is not recommending that patients stop taking ranitidine at this time,” the company said.
Walgreens, Walmart and Rite Aid in the US had earlier taken a similar decision.
Canada and France have removed the drugs from pharmacy shelves. A number of other countries have followed suit.
What should patients do?
Health regulators are urging people taking ranitidine not do discontinue it immediately.
The FDA said, however, that those taking it by prescription should contact health professionals about alternatives. And those buying it over the counter could consider other options.
French authorities also emphasised there was no “acute risk” and patients should not stop the medication or return it to pharmacies.