WASHINGTON -- The problem of angiotensin receptor blockers (ARBs) contaminated with nitrosamines grew a little bigger Friday, with a recall involving a different contaminant from the one responsible for previous warnings.
"Hetero Labs Ltd. in India has announced a recall of 87 lots of losartan potassium tablets (25 mg, 50 mg and 100 mg)," the . "The recalled losartan potassium tablets made by Hetero Labs and distributed by Camber Pharmaceuticals contain the impurity, N-Nitroso-N-methyl-4-aminobutyric acid (NMBA)."
This compound is a known carcinogen in animals and is suspected (but not proven) to cause cancer in humans, the agency noted. "This is the first ARB recall resulting from the presence of NMBA, which is the third type of nitrosamine impurity detected in ARB medicines."
Valsartan was the contamination, and some other drugs in the sartan class subsequently were found to have similar problems. All the previous ARB recalls, however, involved either N-nitrosodimethylamine (NDMA) or N-nitrosodiethylamine (NDEA).
Certain manufacturing processes used by some but not all producers appear to introduce trace quantities of nitrosamines into sartan drugs. Levels generally don't appear to put patients at clinically significant risk but "this doesn't diminish the significance of this issue or the FDA's concerns," the agency emphasized.
The full list of losartan lots covered by this latest recall .