This week, the U.S. Food and Drug Administration expanded its recall of angiotensin II receptor blockers (ARBs) for the fifth time since last summer, when certain lots of valsartan were found to contain traces of the carcinogenic chemical, N-nitroso-diethylamine (NDMA). This most recent recall affects losartan potassium tablets from Torrent Pharmaceuticals, which contain N-methylnitrosobutyric acid (NMBA), a similar chemical contained in tobacco products.
This time, the impurity has been traced back to Hetero Labs, Ltd., a manufacturer in Hyderabad, India. It is not the first time; earlier this year, Torrent announced that it had discovered traces of NMBA in another lot of losartan, the active ingredient of which had also come from same facility.
Hetero Labs has already been the subject of FDA scrutiny. In August of 2017, the company received a warning letter after an investigation the previous year revealed that it had failed to follow Current Good Manufacturing Practices (GCMPs). The FDA found that Hetero Labs had “failed to thoroughly investigate any unexplained discrepancy or failure” of the product and did not properly clean, maintain and sterilize the equipment involved. In an inspection conducted the previous December, an FDA investigator found a “white residue”on an interior gasket that had been allowed to deteriorate.
The current action by Torrent expands the recall to 3 additional lots of losartan potassium and losartan potassium/hydrocholorothiazide. The recall announcement says that Hetero Labs had manufactured the medication’s active pharmaceutical ingredient (API) using an “old route of synthesis.” Although the FDA recently announced that the cancer risk from contaminated ARB medications was not as high as had been feared, NMBA levels are still above acceptable levels.
ARBs are primarily indicated for the treatment of hypertension, or high blood pressure. They work by disabling the cellular receptor for angiotensin, a hormone that causes vascular constriction, essentially widening the blood vessels. Losartan is also used to treat diabetic nephropathy (kidney failure) and a condition known as left ventricular hypertrophy, in which the walls of the heart’s main chamber start to thicken (in some cases, caused by hypertension) and forces the heart muscle to work harder.
Other medications in the ARB class include valsartan, irbesartan and olmesartan, all three of which have been found to contain nitrosamines.
The FDA recommends that patients who have been prescribed an ARB medication continue to do so, as the health risks of stopping may be far greater than that of contracting cancer. Instead, patients who are concerned about nitrosamine contamination should contact the prescribing physician in order to learn about alternative treatments that may be available. It bears repeating that not all ARB medications have been affected by the contamination, so the solution may be as simple as switching to a similar product made by a different drug company. Beyond that, it may be possible to switch to a different class of medication altogether, such as ACE inhibitors or beta blockers. However, only a medical professional can advise you on this matter.