Last reviewed 2026-04-20 · How we verify

Avigan (FAVIPIRAVIR)

Avigan (Favipiravir) is a small molecule antiviral medication originally developed by Toyama Chemical Co., Ltd. It is used to treat influenza and influenza caused by pandemic influenza virus. The exact mechanism of action is not fully understood, but it is believed to work by inhibiting viral RNA polymerase. Avigan is patented and its commercial status is not off-patent. Key safety considerations include potential liver and kidney damage.

At a glance

Approved indications

• Influenza
• Influenza caused by pandemic influenza virus

Common side effects

No common side effects on file.

Key clinical trials

• A Phase 2 Trial Comparing Antiviral Treatments in Early Symptomatic Influenza (PHASE2)
• Finding Treatments for COVID-19: A Trial of Antiviral Pharmacodynamics in Early Symptomatic COVID-19 (PLATCOV) (PHASE2)
• Evaluation of Tolerance and Pharmacokinetic Profile of High Doses of Favipiravir in Healthy Volunteers (PHASE1)
• ISTH/ANRS 0409s INTEGRATE Lassa Fever Study (PHASE2,PHASE3)
• AGILE (Early Phase Platform Trial for COVID-19) (PHASE1,PHASE2)
• Efficacy of Favipiravir Against Ebola (JIKI) (PHASE2)
• Four Different Experimental Drug Regimens to Standard of Care for the Treatment of Symptomatic Outpatients With COVID-19 (PHASE2)
• Assessing Antiviral Treatments in Early Symptomatic RSV (PHASE2)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Avigan CI brief — competitive landscape report
• Avigan updates RSS · CI watch RSS
• Toyama Chemical Co., Ltd. portfolio CI