Favipiravir: A potential COVID-19 Antiviral Drug?

Facts support medical testing to decide if this specific antiviral drug is useful in the COVID-19 diagnosis. Scientists are analyzing evidence for using different drugs in COVID-19 therapy. Among the drugs studied is Favipiravir, also called asT-705 or Avigan, a pyrazine derivative that acts as a viral RNA - dependent polymerase inhibitor, triggering chain termination and preventing elongation of the RNA.


Favipiravir has demonstrated activity against influenza viruses, including oseltamivir-resistant ones, and has been approved for the treatment of novel influenza virus infections in Japan and China. It is a mutagen and has the potential for human teratogenicity as well as embryotoxicity. And also available by mouth and is dosed twice daily for influenza therapy. It was also used for prophylaxis and treatment of Ebolavirus infection with postexposure. It does not have any activity against DNA viruses.

Regarding COVID-19, lay media reported oral Favipiravir (1600 mg twice daily for one day, then 600 mg twice daily) plus inhaled interferon compared with a historical cohort of patients receiving 14 days of lopinavir/ritonavir (Med News Today; 2020 Mar 27) in a non-placebo, open-label trial in Shenzhen, China. Those who received Favipiravir 259793-96-9 and interferon had a median 4-day virus shedding, compared to 11 days in the lopinavir/ritonavir community.

Radiographic improvement was observed in 91 percent of subjects treated with Favipiravir-interferon compared with 62 percent of subjects treated with lopinavir/ritonavir. To date, the results of this study have not been reported in a peer-reviewed journal. A prospective, multicenter, open-label, randomized trial in China was recently reported to compare Favipiravir with Umifenovir (Arbidol), a membrane fusion inhibitor active against influenza viruses (MedRxiv 2020 Mar 27;[ e-pub]). It showed a higher clinical recovery rate among mildly ill patients on day 7 in those on Favipiravir but not among patients with mild or severe illnesses.