The U.S. Food and Drug Administration is temporarily allowing some drug manufacturers to sell blood pressure medicine containing a potential cancer-causing impurity in a bid to balance drug supplies in the U.S.
In a March 20 press release, the FDA allowed drugmakers to sell losartan remaining on the market, which contains the impurity N-Nitroso-N-methyl-4-aminobutyric acid, or NMBA, above the acceptable limit of 0.96 parts per million, or ppm, and below 9.82 ppm.
According to the U.S. regulator, its scientists found that the impurity at levels up to 9.82 ppm had no meaningful difference in cancer risk over a six-month period when compared to a lifetime of exposure to NMBA at 0.96 ppm.
The agency said it expects the companies to manufacture losartan without nitrosamine impurities and replenish the U.S. supply in about six months. It added that distributing losartan containing NMBA up to 9.82 ppm will help maintain adequate losartan supply while companies obtain approval for manufacturing processes that produce nitrosamine-free losartan for patients.
The U.S. regulator recently gave Alkem Laboratories Ltd. an approval for its new generic version of common blood pressure and heart failure drug valsartan in order to ease drug shortages because of the massive recalls of impure blood pressure drugs.
Recalls of blood pressure drugs containing cancer-causing impurities in valsartan began in the U.S. and Europe in July 2018. The ongoing recalls now include losartan and irbesartan products.
Valsartan, losartan and irbesartan are angiotensin II receptor blockers, or ARBs.
Carcinogenic impurities have been found in batches of losartan medications from Hetero Labs Ltd., Novartis AG's unit Sandoz Inc., Macleods Pharmaceuticals Ltd. and Torrent Pharmaceuticals Ltd. The impurities in valsartan have been found in medicine batches from Mylan NV and Teva Pharmaceutical Industries Ltd.