Federal regulators say they have identified the source of the cancer-causing impurities that have contaminated millions of bottles of generic medications for blood pressure and commonly used heart failure. Remembered by the drug manufacturers in the last seven months.
Carcinogens are a chemical byproduct of the process used to synthesize the active ingredient in medicines, which includes valsartan, losartan and irbesartan. People who take those medications may have been exposed to small amounts of impurities for at least four years, following a change in the way companies manufacture the active ingredient, according to the Food and Drug Administration.
An FDA statement released on Friday revealed that contaminants, called N-Nitrosodimethylamine and N-Nitrosodietylamine, are created when "specific chemicals and reaction conditions are present … and can also result from the reuse of materials, such as solvents ". The agency said that byproducts would not have been detected in routine inspections because the process depends on scientists knowing which chemical intruders will be accidentally created during the process, knowing that they said that regulators and companies lacked until recently.
But David Light, executive director of Valisure, an online pharmacy that chemically validates the drugs before shipping them to consumers, said companies may not be cleaning the active ingredients as a cost-saving measure. It would not have been unexpected, he said, that the synthesis process would create pollutants.
"In chemistry, it's pretty easy to put together some chemicals and get a reaction," Light said. "What's hard to do is clean it up and just get the product you want … The manufacturers know, or should have known, about contamination, there are common precision tools to analyze these contaminants, and there are standard procedures to get rid of. they ".
It is unclear how many patients may have been exposed to the carcinogens, but agency leaders have previously estimated that between 1 and 2 million people may have taken the drugs with the impurities.
"We are taking important steps to understand how these impurities occurred, mitigate risk to patients and learn what steps need to be taken to prevent this from happening again in the future," said Commissioner Scott Gottlieb and the Director of the Center for Evaluation and Research. of Drugs Janet Woodcock said in a statement. "While total exposure to these impurities was small for most patients, we are deeply concerned that patients were exposed to this impurity in the first place and that the presence of nitrosamines would not be detected for a period of time."
The agency has minimized the public health risks of contamination, noting that if 8,000 people took the highest dose of a drug, valsartan, for four years, there could be an additional case of cancer. Carcinogens are found in smoked and roasted meats. But the official limit considered "safe" for human consumption carries a much lower risk than possible exposure to contaminated drugs, which causes less than an additional case of cancer in 100,000 people throughout life.
The research that is being developed sheds light on the dark corners of a complex international supply chain of medicines, and in particular the difficulties that can arise when security problems arise for generic medicines, which can be elaborated by multiple drug manufacturers and repackers that can use active products. ingredients of a factory or a small handful of them.
The problems were first detected in medicines that went back to the active ingredient manufacturer Zhejiang Huahai Pharmaceutical Co. in China, but were also found in medicines made from active ingredients manufactured by Hetero Labs in India. Pharmaceutical companies that sell generic drugs include Mylan Pharmaceuticals, Teva Pharmaceuticals, Sandoz, Prinston Pharmaceuticals, ScieGen and Torrent Pharmaceuticals. Some of these companies also sell the medicines under different labels. For example, Prinston recalled batches of drugs that were labeled as Solco Healthcare, and Teva recalled batches labeled as made by Actavis and Major Pharmaceuticals.
Valsartan has been in short supply since August, and the agency warned in its statement that "other types of products could soon fall into shortages," without offering specific details. The agency urges patients to continue taking their medications until a pharmacist or doctor provides another option because they need to balance the risks of uncontrolled blood pressure with an increased risk of cancer.
A spokeswoman for the FDA said the investigation is continuing and it is impossible to predict how many more withdrawals there could be. He said drug makers will continue to test their products and remember the pills that contain impurities during an interim limit that the FDA set to ensure that patients can continue to have access to the drugs in the short term.
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