Losartan, a common blood pressure drug, is being proposed as a treatment for COVID-19. The idea comes from researchers at the Sackler Faculty of Medicine in Israel. They published their commentary on PubMed last month. The proposal is not based on new lab experiments or clinical trials. It is an observation-based suggestion, drawn from how the drug works and how the virus enters human cells.
The virus, SARS-CoV-2, uses a protein called ACE2 as its entry point into cells. This is the same receptor used by the SARS virus from the early 2000s. The Israeli team, from the Department of Human Molecular Genetics and Biochemistry, noted this similarity. They argue that angiotensin receptor blockers, or ARBs, could reduce the aggressiveness and mortality of the infection. Their tentative suggestion is to use drugs like losartan, which are already available and approved for other uses. They believe such a treatment would likely be resistant to new coronavirus mutations.
Peter Sever, a professor of clinical pharmacology and therapeutics at Imperial College London, supports the idea. He said these drugs could reduce the risk of serious lung disease following infection. That is a key point. The disease, as of March 18, 2020, had infected over 180,000 people and killed more than 7,000. The primary cause of death in severe cases is lung damage and acute respiratory distress. If a cheap, widely available drug could lower that risk, the consequences would be massive.
But the proposal is not without controversy. Other scientists have raised concerns that ARBs might actually increase infection risk. The mechanism is the same one the Israeli team is banking on. ACE2 is the virus’s door into cells. Some worry that drugs affecting the renin-angiotensin system could upregulate ACE2, giving the virus more doors to open. The Israeli team and Sever argue the opposite — that blocking the downstream effects of the virus’s entry could protect the lungs.
The stakes are high. The drugs relax veins and arteries, lower blood pressure, and help the heart pump blood more easily. They are used to treat chronic kidney disease, heart failure, and kidney failure in diabetes. Millions of people around the world take them daily. If ARBs prove harmful in the context of COVID-19, those patients could face increased risk. If they prove protective, the drugs could be deployed rapidly.
The Israeli researchers said that after successful safety tests in animals, a series of studies and tests should follow. That is the next step. No clinical trials have been announced yet. No randomized controlled data exists. The proposal remains a hypothesis, grounded in known biology but untested against the new virus.
The timeline matters. The pandemic is moving fast. Hospitals are filling. Ventilators are in short supply. A drug that is already on pharmacy shelves, already approved, and already understood could skip years of development. Losartan is generic. It is cheap. It can be taken orally. If it works, it could be used outside of hospitals, potentially reducing the burden on intensive care units.
If it does not work, or if it makes things worse, the consequences could be severe. Patients with hypertension or heart disease — already at higher risk from COVID-19 — could be harmed by a well-intentioned but incorrect treatment. That is why the Israeli team calls for animal safety tests first, then a series of studies.
The commentary is a starting point, not a conclusion. It lays out a rationale. It names a drug. It points to a path forward. Now the work begins. Researchers need to test the idea in animals. Then in humans. Then in large trials. The clock is running.
