Online pharmacy Valisure reported that it found a new cancer-causing impurity in some versions of widely prescribed blood pressure medicine valsartan, but U.S. regulators said on Tuesday that the amount in the drugs was well below levels deemed to be potentially harmful.
Connecticut-based Valisure informed the U.S. Food and Drug Administration in a citizen petitihere last week that it had found through its own testing an impurity called dimethylformamide (DMF) in some batches of the drug. DMF is classified as a probable human carcinogen by the World Health Organization.
The FDA said it would review the petition, but “it is important to note that the amounts of DMF being reported are more than 100 times less than those determined by international standards as the level of concern to patients.”
Valisure analyzed valsartan from multiple manufacturers including Novartis AG and several generic manufacturers. Valsartan is the generic name of Novartis’ Diovan.
The amount of DMF found ranged from 8 nanograms per pill to over 100,000 nanograms per pill, the pharmacy said. All were significantly below the current permissible level of 8.8 milligrams per day.