Since last year, the FDA has been investigating NDMA and other impurities in blood pressure and heart failure medicines known as angiotensin receptor blockers or ARBs. Numerous recalls have been launched as the FDA found "unacceptable levels" of nitrosamines in several of those common drugs containing valsartan. So far, NDMA has been found in ranitidine in low levels and we are not calling for consumers and patients to stop taking ranitidine at this time," he said. The FDA will share more information with the public and industry as we learn more throughout the investigation." Woodcock said the FDA is working with international regulators and industry partners to determine the source of the ranitidine impurity.

Some heartburn medications sold under the brand-name Zantac contain a cancer-causing impurity, the U.S. Food and Drug Administration warned Friday. The FDA said low levels of a nitrosamine impurity called N-nitrosodimethylamine (NDMA) were found in the medications. Despite the warning issued Friday, the FDA said patients do not need to stop taking Zantac yet. The FDA said patients who have been prescribed Zantac should talk to their physician if they want to stop taking the medication. People taking OTC ranitidine could consider using other OTC medicines approved for their condition.