Last checked at 
* Four products recalled; over-the-counter ones not affected
* UK regulator says recall a "precautionary measure"
* Regulators investigating ranitidine drugs for impurities
(Adds details on products affected, context on other drugmakers
halting supply)
By Justin George Varghese
Oct 8 (Reuters) - GlaxoSmithKline is recalling
prescription-only versions of its popular heartburn medicine
Zantac as a "precautionary measure" due to a probable
cancer-causing impurity in the drugs, Britain's medicines
watchdog said on Tuesday.
The move follows an investigation by U.S. and European
regulators into the presence of a potentially cancer-causing
impurity in Zantac and generic versions known chemically as
ranitidine, which are also used to treat stomach ulcers.
The U.S. Food and Drug Administration (FDA) said last week
levels of the impurity were "unacceptable".
Britain's Medicines and Healthcare products Regulatory
Agency (MHRA) said https://www.gov.uk/drug-device-alerts/class-2-medicines-recall-zantac-injection-50mg-2ml-zantac-syrup-150mg-10ml-zantac-tablets-150mg-zantac-tablets-300mg-el-19-a-24
GlaxoSmithkline (GSK) was recalling four prescription-only
Zantac medicines: a syrup, an injection and tablets of 150 and
300 milligram dosages.
Over-the-counter products - Zantac 75 Relief and Zantac 75
Tablets - are produced by a different company and are not
affected by the recall, it added.
The MHRA said GSK was recalling all unexpired stock of the
medicines from pharmacies due to possible contamination of
carcinogen N-nitrosodimethylamine (NDMA).
The British company confirmed the recall.
"GSK is continuing with investigations into the potential
source of the NDMA," a company spokesman said, adding these
investigations include continued engagement with its suppliers
and with external laboratories to conduct tests on finished
product batches of Zantac.
The MHRA said healthcare professionals had been told to
"stop supplying the products immediately, quarantine all
remaining stock and return it to their supplier".
"We are advising that patients should not to stop taking
their medication, and do not need to see their doctor until
their next routine appointment but should seek their doctor's
advice if they have any concerns," the MHRA said.
GLOBAL STOPPAGE
U.S. and European health regulators said last month they
were reviewing the safety of ranitidine, after online pharmacy
Valisure flagged the impurities to them.
The FDA said Valisure's higher temperature testing method
generated very high levels of NDMA from the ranitidine drugs.
After checking the over-the-counter drugs using a low-heat
method of testing, the FDA said it found much lower levels of
NDMA than was discovered with a higher temperature test employed
by Valisure.
The U.S. regulator has asked ranitidine makers to conduct
their own testing to assess levels of the impurity and to send
samples of their products for testing by the agency.
Swiss drugmaker Novartis halted global distribution
of its ranitidine drugs last month.
Last week, Walmart Inc joined pharmacy chains CVS
Health Corp, Walgreens Boots Alliance Inc and
Rite Aid Corp in suspending the sale of over-the-counter
heartburn drugs containing ranitidine.
Canada's health authorities have asked makers of the drugs
to halt distribution as they gathers more information. Last
month, regulators in Hong Kong pulled four products, while in
Ireland 13 products containing ranitidine were recalled.
NDMA had previously been found in some blood pressure
medicines from a class of drugs known as angiotensin II receptor
blockers, or ARBs. The impurity was believed to have been
introduced by changes in the manufacturing process.
(Reporting by Justin George Varghese in Bengaluru; Editing by
Deepa Babington and Mark Potter)
