Favipiravir 400 mg Tablets – Broad-Spectrum Antiviral for Influenza and COVID-19

 What is Favipiravir 400 mg?

Favipiravir 400 mg is a broad-spectrum antiviral medication originally developed to treat influenza. It has also gained attention for its use in managing mild to moderate COVID-19 cases and other RNA virus infections under emergency or investigational use. Favipiravir works by inhibiting RNA-dependent RNA polymerase (RdRp), an essential enzyme the virus needs to replicate.

• Drug Class: RNA polymerase inhibitor
• Form: Oral tablet
• Strength: 400 mg
• Common Brand Names: FabiFlu, Avigan (Japan), Favicovir

Mechanism of Action

Favipiravir is a prodrug, which means it is converted inside the body to its active form – favipiravir ribofuranosyl-5′-triphosphate. This active compound targets and inhibits viral RNA polymerase, preventing the replication of the virus’s genetic material and thereby stopping the spread of infection.

Dosage and Administration

Always follow the prescribed dosage from a healthcare professional. The following is a typical regimen for adults.

COVID-19 Treatment Dosage (example protocol):

• Day 1 (Loading Dose):
  → 1800 mg twice daily (total 3600 mg/day)
• Day 2 onwards (Maintenance Dose):
  → 800 mg twice daily
• Treatment Duration: 7–14 days depending on clinical condition

For Influenza (as used in Japan):

• Day 1: 1600 mg twice daily
• Day 2–5: 600 mg twice daily

Tablets should be taken with water, after meals, to reduce gastrointestinal discomfort.

Benefits

• Inhibits replication of RNA viruses including influenza and SARS-CoV-2
• Potential to reduce viral load and improve clinical symptoms faster
• Oral administration makes it easy to use in outpatient settings
• May prevent progression of mild COVID-19 to severe disease (under specific protocols)

Side Effects

Common Side Effects:

• Nausea
• Vomiting
• Diarrhea
• Headache
• Elevated liver enzymes
• Hyperuricemia (high uric acid levels)

Rare but Serious Effects:

• Liver dysfunction
• Psychiatric symptoms (rare)
• Blood disorders (e.g., neutropenia)

Warnings and Precautions

• Pregnancy: Contraindicated. Favipiravir can cause fetal harm. Women of childbearing age must use effective contraception during and after treatment.
• Breastfeeding: Not recommended while on favipiravir.
• Gout or Hyperuricemia: Use with caution; favipiravir may increase uric acid levels.
• Liver Disease: Monitor liver function during therapy.

Drug Interactions

• Caution with drugs that affect uric acid metabolism (e.g., allopurinol)
• May interact with pyrazinamide, theophylline, or repaglinide
• No significant interactions with most common antiviral or antibiotic medications

Always inform your doctor about any other medications or supplements being taken.

Storage Instructions

• Store in a cool, dry place at room temperature (15°C to 25°C / 59°F to 77°F)
• Protect from direct sunlight and moisture
• Keep out of reach of children