File this under “Go Figure”:

FDA identifies contamination source in blood pressure medicines used by millions

Federal regulators say they’ve identified the source of the cancer-causing impurities that have tainted millions of bottles of commonly used generic blood pressure and heart failure medications recalled by drugmakers over the last seven months.

The carcinogens are a chemical byproduct of the process used to synthesize the active ingredient in the drugs, which include valsartan, losartan and irbesartan. People who take those drugs may have been exposed to trace amounts of impurities for at least four years, after a switch in how companies manufactured the active ingredient, according to the Food and Drug Administration.

An FDA statement Friday disclosed that the contaminants, called N-Nitrosodimethylamine and N-Nitrosodiethylamine, are created when “specific chemicals and reaction conditions are present . . . and may also result from the reuse of materials, such as solvents.” The agency said those byproducts would not have been detected in routine inspections because the process depends on scientists knowing which chemical intruders are likely to be accidentally created during the process, knowledge that they said regulators and companies lacked until recently.

But David Light, chief executive of Valisure, an online pharmacy that chemically validates drugs before shipping them to consumers, said it’s possible that companies weren’t cleaning up the active ingredients as a cost-saving measure. It wouldn’t have been unexpected, he said, that the synthesis process would create contaminants.

“In chemistry, it’s pretty easy to throw some chemicals together and get a reaction,” Light said. “What’s hard to do is to clean it up and only get the product you want . . . . The manufacturers know, or should have known, about the contamination. Common precision tools exist to analyze these contaminants, and there are standard procedures for getting rid of them.”

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The unfolding investigation shines a light on the dark corners of a complex, international drug supply chain — and in particular the difficulties that can crop up when safety issues arise for generic drugs, which may be made by multiple drug manufacturers and repackagers that may use active ingredients from one factory or a small handful of them.

https://www.washingtonpost.com/amphtml/health/2019/01/25/cancer-causing-...