A number of blood pressure drugs are now under investigation by the United States Food and Drug Administration (FDA) for allegedly containing impurities that might pose a cancer risk to its users. The investigation on the specific class of blood pressure drugs began last summer, and the FDA has already recalled a number of them from the pharmacy shelves.
The type of blood pressure drug that is under investigation are angiotensin II receptor blockers or ARBs for short. ARBs usually contain active chemicals such as losartan, irbesartan, and valsartan. Dr. Janet Woodcock, a researcher for the FDA's Center for Drug Evaluation and Research, revealed that these types of drugs initially started to contain impurities sometime in 2010. The drugs that were found to contain impurities came from different manufacturers from around the world, but most of them had come from China.
The synthetic processes to create these drugs were reportedly changed by a Chinese manufacturer, which in turn resulted in an unwanted chemical reaction. The reaction resulted in the presence of a genotoxic substance called N-nitrosodimethylamine, or NDMA. The substance is commonly found as a byproduct in the production of pesticides and it is highly toxic to humans because it can directly affect the body's DNA replication process.
Dozens of nations, including the European Union, had already initiated recalls for these types of drugs after finding that they contained NDMAs. Reports from several regulators indicated that a huge amount of valsartan-based drugs that came from Zhejiang Huahai Pharmaceuticals in China had contained these impurities.
The FDA has revealed that while the discovery of these impurities is more recent, the contaminated drugs could have been in circulation since 2014 in the United States. The genotoxic impurities found in ARB drugs is believed to be the result of reusing materials during the synthetic process. Due to the low levels of the impurities found in the drugs and because they weren't really looking for it, regulators and agencies had a hard time detecting them.
The FDA reports that over 60 million Americans take blood pressure drugs each year, specifically losartan, valsartan, and irbesartan. However, the likelihood of these tainted drugs directly causing cancer is relatively low. According to the FDA, only one in 8,000 patients who take the drug over the course of four years will develop cancer. Despite the low probability, the FDA is not taking any chances.
The FDA along with other inspectors from agencies in other countries routinely checks and inspects manufacturing plants around the world. Some companies who do not meet regulations are flagged and their products are barred from being imported and distributed. Companies that refuse FDA inspection are immediately blacklisted. The FDA also works with the Chinese government to inspect facilities in its country. However, some companies do make it hard for the FDA to gain access to their facilities.
