Last reviewed 2026-04-22 · How we verify

Camostat mesylate

Camostat mesylate is a serine protease inhibitor that blocks transmembrane protease serine 2 (TMPRSS2), preventing viral entry and reducing inflammatory protease activity.

Camostat mesylate is a serine protease inhibitor that blocks transmembrane protease serine 2 (TMPRSS2), preventing viral entry and reducing inflammatory protease activity. Used for COVID-19 (SARS-CoV-2 infection), Acute respiratory distress syndrome (ARDS).

At a glance

Mechanism of action

Camostat inhibits TMPRSS2, a cellular serine protease involved in the activation of spike proteins for viral cell entry, particularly relevant for respiratory viruses including SARS-CoV-2. By blocking this protease, the drug reduces viral infectivity and may also suppress excessive protease-driven inflammation in tissues. This dual mechanism makes it potentially useful in viral infections and inflammatory conditions.

Approved indications

• COVID-19 (SARS-CoV-2 infection)
• Acute respiratory distress syndrome (ARDS)

Common side effects

• Diarrhea
• Nausea
• Abdominal discomfort
• Elevated liver enzymes

Key clinical trials

• The Impact of Camostat Mesilate on COVID-19 Infection (PHASE1, PHASE2)
• Effect Camostat for Kidney Protection in Chronic Kidney Disease (PHASE2)
• Camostat Mesylate for Protein-losing Enteropathy After Fontan Operation (PHASE2)
• Camostat Mesilate Treating Patients With Hospitalized Patients With COVID-19 (PHASE2)
• The Potential of Camostat in COVID-19 (PHASE2)
• ACTIV-2: A Study for Outpatients With COVID-19 (PHASE2, PHASE3)
• Multiple-dose Study of FOY-305 in Japanese Healthy Adult Male Subjects (PHASE1)
• A Study of FOY-305 in Patients With SARS-Cov-2 Infection (COVID-19) (PHASE3)

Primary sources

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