After the U.S. regulator found potentially cancer-causing chemical N-Nitrosodimethylamine (NDMA) in the ranitidine-class heartburn medications, including Zantac, the Korean public grew increasingly worried about carcinogen risks.

To calm the jitters, the Korean Medical Association sent an urgent message to its member doctors on Monday, recommending they prescribe alternative drugs.

“The government and pharmaceutical firms should take charge of noticing the carcinogen detection in ranitidine drugs and announcing the follow-up measure,” KMA said.

“Doctors and medical institutions should prescribe other medications if a patient demands a replacement for ranitidine-class medicine.”

If a physician prescribes an alternative drug, the patient should pay his or her contribution, and the government and the drugmaker should be responsible for an additional cost, the doctors’ group said.

KMA went on to say that it sent such message to minimize the confusion among physicians and to resolve the public anxiety over the carcinogen fears in ranitidine drugs, including Zantac, especially after the nation suffered chaos during the valsartan recall last year.

“When the valsartan was recalled, doctors used authorized drugs only and tried to soothe patients,” KMA Spokesperson Park Jong-hyuck said. “The food and drug safety ministry poorly responded to the valsartan debacle and Invossa suspension. The ministry is taking the issue too lightly.”

Doctors are sharing their opinions that ranitidine drugs were problematic, Park added. “As our members were curious about this issue, we sent the message to warn about the risk. It was a pre-emptive response,” he said.

The U.S. Food and Drug Administration announced on Sept. 13 that it detected NDMA in ranitidine-class drugs including Zantac. NDMA is a carcinogen that had been found in some valsartan-containing hypertension treatments in Korea.

As the NDMA contamination was at a low level, the FDA did not order a suspension of the medication or recall and was reviewing the drug’s safety.

The food and drug safety ministry on Monday last week announced that it did not find NDMA in ranitidine products that the ministry collected and inspected.

Although the recent test did not detect NDMA, the ministry said it would continue to expand the collection and testing of all locally manufactured ranitidine raw materials from 11 manufacturers and 395 pharmaceutical products using the raw materials.