United States health regulators are asking five drug makers to recall their versions of a widely used diabetes medicine, after laboratory tests found elevated levels of a cancer-related pollutant.
The Food and Drug Administration (FDA) said Thursday night that several batches of the drug metformin tested positive for unsafe levels of N-nitrosodimethylamine, a possible cancer-causing chemical that can form as a manufacturing by-product.
The agency has stepped up the tests after the chemical was found in dozens of shipments of blood pressure and heartburn medications last year, prompting the recall of Zantac and other popular over-the-counter and prescription medications.
Metformin tablets are a staple of diabetes care as they reduce excess blood sugar. People with type 2 diabetes use metformin alone or with other medications to help control those levels. More than 34 million people in the United States suffer from this disease.
Patients should continue to take metformin until their doctor can prescribe a replacement, the FDA said in a statement, noting the risks of discontinuing it. Regulators are still evaluating whether recalls will lead to shortages, but noted that several other companies make generic versions of the drug that appear unaffected by the problem.
The drug maker Apotex Corp. recalled its extended-release metformin distributed in the United States earlier this week, after the FDA found contamination in a batch. Apotex said in a statement that it voluntarily withdrew all supplies of the drug “as a precaution.” The company said it stopped selling the drug in the country in February 2019 and that there is little left on the market.
The FDA announcement did not mention the other four manufacturers who were asked to recall their products.
The agency noted that no contamination problems have been found in the immediate-release metformin.
The FDA is responsible for ensuring that drugs for the United States market are manufactured under safe sanitary conditions that meet federal quality standards. However, government inspectors have repeatedly criticized the agency for failing to comply with the review of overseas manufacturing plants, as the pharmaceutical supply chain has increasingly extended to Asia. In March, the FDA suspended almost all US and foreign inspections due to safety concerns and travel restrictions caused by the coronavirus outbreak.
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