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FDA: Actual risk from impurities in valsartan, losartan likely lower than published estimates
In a statement released today on safety issues with angiotensin II receptor blockers, the FDA wrote that risk for harm to patients from nitrosamine impurities is likely lower than has been stated in previous estimates, and that the risks of stopping the medications must be considered.
“We continue to encourage patients talk to a health care professional if they have questions about their medicine, as the risks of stopping taking an ARB product for treating high blood pressure and heart failure greatly outweighs the potential risk of exposure to trace amounts of nitrosamines,” Janet Woodcock, MD, director of the FDA’s Center for Drug Evaluation and Research, wrote in the statement.
As Healio previously reported, numerous lots of valsartan and losartan from various manufacturers have been recalled due to excessive levels of N-Nitrosodimethylamine (NDMA) and other nitrosamine impurities.
Woodcock wrote, however, that “the actual risk to patients is likely much lower than our estimates, which reflect a scientific assessment of the highest possible exposure. We initially estimated that if 8,000 people took the highest valsartan dose (320 mg) containing NDMA from the recalled batches daily for 4 years, there may be one additional case of cancer over the lifetimes of those 8,000 people. In reality, the vast majority of patients exposed to NDMA through ARBs received much smaller amounts of the impurity than this worst-case scenario, and, since not all ARBs are affected, it’s very likely that a patient taking an ARB for 4 years would not have always received one of the affected products.”
In addition, she wrote, the number of patients who returned their medications is likely greater than the number who were actually affected, because lot numbers are not always identified on prescription bottles and thus some patients may have returned medications that were not part of a recall.
Patients and physicians should consult the FDA’s publicly available list of ARB products which are and are not affected, she wrote.
The FDA has modified its inspection processes in hopes of detecting problematic products before they are available on the market and will apply what it has learned about the causes of nitrosamine impurities in ARB active pharmaceutical ingredients to other drugs with similar manufacturing processes, Woodcock wrote.
“Ultimately, our goal is to be certain that no ARBs with unacceptable impurity levels reach patients. Based on our current assessments, including lab testing, the agency has identified 43 ARB medications that have been determined not to contain any nitrosamine impurities. As we continue our assessments and as companies continue to manufacture ARBs without nitrosamine impurities to replenish the U.S. supply, we expect this figure to rise,” she wrote. “We know that ARBs can be produced without nitrosamine impurities, and we are working with manufacturers to reach that point.”
Disclosure: Woodcock is an employee of the FDA.