Nafamostat mesylate (INN), a synthetic serine protease inhibitor, is a short-acting anticoagulant,[1] and it is also used for the treatment of pancreatitis.

[2] Nafamostat is a fast-acting proteolytic inhibitor and used during hemodialysis to prevent the proteolysis of fibrinogen into fibrin.

[3] The mechanism of action of nafamostat is as a slow tight-binding substrate, trapping the target protein in the acyl-enzyme intermediate form, resulting in apparent observed inhibition.

[citation needed] This drug has been identified as a potential therapy for COVID-19,[8][9] with clinical trials in Japan possibly set to begin in March 2020.

[10] With evidence that nafamostat is a potent anti-viral inhibitor in lung cells, a second round of clinical trials in Korea has begun with 10 hospitals participating.