The announcement comes after patients' anxiety has increased since the Singapore Health Sciences Agency (HSA) announced that it detected N-Nitrosodimethylamine (NDMA), a potentially carcinogenic substance, in some drugs containing metformin, a substance used to treat diabetes.

Such fears are mainly due to the recent history of finding NDMA in drugs, such as the valsartan-based antihypertensive drug crisis in August 2018 and ranitidine-based heartburn drug crisis in September. Until now, the ministry has been responding by banning the drugs that contain NDMA. However, the KDA noted that this time, the ministry needs to take more swift action since metformin has no alternative treatment options.

"There are 640 medicine products that contain metformin in Korea," the association said. "The drugs are used by 2.4 million diabetic patients, which accounts for 80 percent of Korea's diabetic population."

In contrast to hypertension drugs or heartburn medications, which have a variety of alternative medicines, metformin does not have an alternative medicine, the association said. The association stressed that the Ministry of Food and Drug Safety needs to give a clear explanation and have a more direct and swift approach on how to handle the matter.

"During the valsartan crisis of last year, the ministry has said they would have comprehensive management plans," the association said. "However, there has been little to no progress on the matter."

The ministry has also not even made an official announcement on whether the raw materials of the companies in question have been imported into Korea, the association added.

The association noted that making the drugmakers to check their products autonomously is not a solution, either.

"In the U.S., Europe, and Japan, relevant agencies conduct direct research on products that pose public health dangers," the association said. "Notably, the FDA has been publishing drugs that they have confirmed to be safe on its website."

The Ministry of Food and Drug Safety should also dissolve the public's concerns through a direct investigation, the association added.

KDA stressed that the role of doctors in instructing patients not to stop diabetes drugs containing metformin is also important.

"According to the Singapore authorities, only three out of 46 metformin items have detected NDMA above baseline," the association said. "Since the three items have only started to be prescribed since last year and none of the previous products contained NDMA, there is no need to expand the fear to all products containing metformin."

Patients should follow their doctor's guidance until the authorities release the results of its investigation as random discontinuation of the drug may cause problems such as hypertension, it added.