As part of the ongoing safety investigation of potentially carcinogenic impurities detected in angiotensin II receptor blocker (ARB) medications, the Food and Drug Administration (FDA) has released a list of 40 ARBs that do not contain any known nitrosamine impurities. The agency anticipates the list will be updated with more medications as their assessment continues.

ARBs are a class of drugs used to treat hypertension and heart failure. Nitrosamines are known environmental contaminants found in water and foods (eg, meats, dairy, vegetables) that are classified as probable human carcinogens. The FDA first issued a statement in August 2018 regarding generic versions of one ARB, valsartan, that were found to contain an impurity that did not meet the agency’s safety standards.

An internal working group from the FDA – in collaboration with global regulators – has been working to minimize risk to patients by ensuring access to safe ARBs or acceptable alternatives and removing affected agents from the US supply chain. However, certain shortages have occurred for drugs that have been removed from the market due to an unacceptable level of nitrosamine impurity (eg, valsartan, losartan).

As a result, the agency is allowing the temporary distribution of specific lots of losartan that contain nitrosamine above the interim acceptable intake limit as the risk of abrupt discontinuation outweighs the low risk associated with drugs containing these impurities. According to the FDA, nitrosamine-free losartan is expected to become available in the US in about 6 months as companies work to replenish the supply.

“Our goal is for this information to help healthcare providers as they consider acceptable treatment options for their patients. Our assessment takes into consideration testing for impurities conducted by the FDA’s laboratories, an evaluation of the manufacturing process used by multiple manufacturers of the active pharmaceutical ingredient (API) found in ARB medicines, as well as other information available to the agency from manufacturers and international regulators,” according to an FDA press statement.

The list also contains other products that are being evaluated. For these drugs, nitrosamine impurities have either been undetected or are below the intake limits, and thus can still be distributed.

For more information visit FDA.gov.

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This article originally appeared on MPR