Latest ARB Recall Triggered by New Impurity

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Hetero Labs recalls losartan potassium tablets due to presence of N-Nitroso-N-methyl-4-aminobutyric acid.

In announcing another recall of generic angiotensin II receptor blocker (ARB) drug products on March 1, 2019, FDA identified a third impurity that is a potential human carcinogen.

The impurity N-Nitroso-N-methyl-4-aminobutyric acid (NMBA) was found at levels higher than the FDA’s interim acceptable intake limits in losartan potassium tablets manufactured by Hetero Labs in India and distributed by Camber Pharmaceuticals. Previous recalls were initiated due to the presence of N-Nitrosodimethylamine (NDMA) and N-Nitrosodiethylamine (NDEA) impurities in ARB medicines.

FDA noted in a statement that the increased risk of cancer to patients with NMBA exposure appears to be the same for NDMA exposure but less than the risk from NDEA exposure. In ongoing investigations, the agency has determined that the impurities may be the result of chemical reactions in the manufacturing of the API or the reuse of materials such as solvents.


FDA developed tests to detect and measure NDMA and NDEA impurities in ARB medicines and is conducting an organic chemistry analysis to develop tests methods to detect additional nitrosamine impurities, according to the statement.

Source: FDA