Changes in utilization of generic ARBs following product recalls in the United States

Investigators from Brigham and Women's Hospital in Boston wondered how use of angiotensin receptor blockers (ARBs) might have shifted after FDA was forced to recall several lots of the antihypertensives in 2018.

Investigators from Brigham and Women's Hospital in Boston wondered how use of angiotensin receptor blockers (ARBs) might have shifted after FDA was forced to recall several lots of the antihypertensives in 2018. The regulator took action in response to the discovery of potentially carcinogenic impurities—mainly in lots of valsartan but also, to a lesser extent, in some losartan and irbesartan products. The researchers, by tapping into a nationwide commercial claims database, were able to analyze 9 million generic ARB prescriptions filled by 1.7 million unique users before and after the recalls began. They found that generic valsartan as a share of overall ARB use fell to 10% by March 2019 from 21% in June of the previous year, when FDA issued its first recall of the drug. After the agency starting pulling batches of losartan off the market in November 2018, utilization of that ARB slipped from 73% to 71%. Overall, generic versions of valsartan, losartan, and irbesartan affected by recalls made up 37% of overall generic ARB use in June 2018—a share that declined to 21% by the following March. Prescriptions for olmesartan and irbesartan, meanwhile bumped up 2 percentage points each over that time span. Researchers suspect that the reason total volume of generic ARB prescriptions did not flag was because patients taking recalled products may have simply switched to a different ARB, thus preventing treatment disruptions.