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.