Telmisartan is an angiotensin II inhibitor. It blocks the action of angiotensin II through its antagonistic function on the receptors for this substance naturally present in the body, which causes contraction of the arteries and increases arterial pressure. Telmisartan is therefore an antihypertensive drug used in the treatment of high blood pressure and chronic renal failure. Telmisartan has several advantages: its half-life is 24 hours (longer than other angiotensin II receptor antagonists) and it does not alter the metabolism of bradykinin (unlike ACE inhibitors), which avoids associated side effects such as coughing.

Studies have shown that during SARS-Cov-6 infection, alveolar cell ACE2 protein is targeted. The loss of the enzymatic action of ACE2 leads to an increase in the concentration of angiotensin II. This would be the starting point for the cytokine storm described in the most affected Covid-19 patients. For this reason, clinical studies have been initiated to test the effect of telmisartan on the development of acute respiratory distress syndrome (ARDS) in Covid-19 patients.