Favipiravir

What it is and how it works

Favipiravir is a prodrug converted intracellularly to favipiravir ribofuranosyl-5′-triphosphate, which selectively inhibits viral RNA-dependent RNA polymerase and induces lethal mutagenesis in RNA viruses. It has broad in vitro activity against influenza and other RNA viruses.

Indications

Approved in Japan for novel or re-emerging pandemic influenza when other antivirals are ineffective or insufficient; it has been authorised in some countries, including Iran, for COVID-19 under emergency or conditional arrangements, although clinical benefit there is uncertain.

Dosage and administration (summary)

Oral; for influenza the approved regimen is 1600 mg twice daily on day 1 followed by 600 mg twice daily on days 2–5; regimens used for other indications follow national protocols.

Contraindications

Pregnancy or suspected pregnancy, and hypersensitivity to favipiravir.

Warnings and precautions

Favipiravir is teratogenic and embryotoxic in animals; pregnancy must be excluded before treatment, women and men must use effective contraception during and for a period after treatment, and the drug passes into semen. It raises serum uric acid and may cause hepatic enzyme elevation, diarrhoea and neutropenia; caution in gout and hepatic impairment.

Pregnancy

Contraindicated in pregnancy because of teratogenic risk.

Storage and supply

Store below 30 °C, protected from moisture.

Source: reference summary prepared from the EU SmPC/EPAR, BNF and WHO Model Formulary. The approved product information in Iran governs.