Scientists are scrambling to find effective COVID-19 treatments. Researchers have explored surprising and creative drug combinations to treat the novel virus, which has severely burdened numerous healthcare systems, workers, patients, and their loved ones. One of the more recent drug inquiries involve angiotensin-converting-enzyme inhibitors, or ACEI. These drugs typically treat high blood pressure and heart failure by dilating blood vessels through their actions in the renin-angiotensin-aldosterone system (RAAS). Cardiovascular experts from the University of Texas Health San Antonio recently explained the potential role of ACEI in patients with COVID-19 in their April 14th publication.

What drove their initial investigation were two findings from the literature: 1) COVID-19 patients with cardiac problems have worse outcomes than those without such complications and 2) the coronavirus is thought to enter the lungs by attaching to a cellular receptor called ACE2, which is also a component in the RAAS system.

According to Rico-Mesa et al., it is too early to know how ACEI affects COVID-19 patients.

Some research indicates that ACEI could worsen COVID-19 infection. When ACEI is introduced to the body, ACE2 receptors are thought to “upregulate,” or increase in number. Given the high affinity of COVID-19 to these receptors, ACEI could ultimately cause increased lung infection. This proposed mechanism resembles cupcake and muffin pans: if more slots are made in the pan, there is more room for the batter to fill. Similarly, if there are more ACE2 receptors, there is more opportunity for COVID-19 to infect lung cells.

Interaction between SARS-CoV-2 and the Renin–Angiotensin–Aldosterone System (Vaduganathan et al., 2020)

However, others propose that ACEI can actually improve coronavirus infections. Some hypothesize that ACEI disrupts the RAAS system altogether, causing a widespread reduction in ACE2 receptor integrity. This would, therefore, leave less room for COVID-19 lung infection (by ruining the “muffin pan” altogether).

Due to the lack of evidence for increased mortality in COVID-19 patients using ACEI, the American College of Cardiology and other institutions recommend that previous users of ACEI continue such treatment if they contract the virus, unless otherwise prescribed by their physician. The pandemic is constantly changing, so current protocols will be updated as more data become available. The hypothesized role of ACEI for COVID-19 treatment highlights the need for caution while proceeding with experimental treatments. Further, this conclusion emphasizes to the public that sensationalized findings must be met with skepticism.


Rico-Mesa JS, White A, Anderson AS. 2020. Outcomes in Patients with COVID-19 Infection Taking ACEI/ARB. Current Cardiology Reports 22: 31.

Vaduganathan, M., Vardeny, O., Michel, T., McMurray, J. J. V., Pfeffer, M. A., & Solomon, S. D. 2020. Renin–Angiotensin–Aldosterone System Inhibitors in Patients with Covid-19. New England Journal of Medicine 382: 1653–1659