FDA Temporarily Allows Increased Levels of NMBA in Losartan Amid Recalls

By Kelly Young

Edited by André Sofair, MD, MPH, and William E. Chavey, MD, MS

The FDA is allowing manufacturers to temporarily sell losartan that has levels of N-Nitroso-N-methyl-4-aminobutyric acid (NMBA), which is possibly carcinogenic, above the interim acceptable limit.

The decision comes amid an ongoing, large-scale recall of certain angiotensin-receptor blockers because they contain higher-than-acceptable levels of NMBA and other nitrosamines.

The agency will allow distribution of losartan with NMBA levels above 0.96 parts per million (ppm) but below 9.82 ppm. FDA researchers found that exposure at levels up to 9.82 ppm for 6 months was not associated with increased cancer risk compared with a lifetime of exposure at 0.96 ppm.

The FDA expects losartan without these impurities to be back on shelves in roughly 6 months.