Favipiravir: Pharmacokinetics and Concerns About Clinical Trials for 2019-nCoV Infection.

An outbreak of 2019-nCoV infection has spread across the world. No specific antiviral drugs have been approved for the treatment of COVID-2019. In addition to the recommended antiviral drugs, such as interferon-ɑ, lopinavir/ritonavir, ribavirin, and chloroquine phosphate, some clinical trials focusing on virus RNA-dependent RNA polymerase (RdRp) inhibitors have been registered and initiated. Favipiravir, a purine nucleic acid analog and potent RdRp inhibitor approved for use in influenza, is also considered in several clinical trials. Herein, we summarized the pharmacokinetic characteristics of favipiravir and possible drug-drug interactions from the view of drug metabolism. We hope this will be helpful for the design of clinical trials for favipiravir in COVID-2019, as data regarding in vitro virus inhibition and efficacy in preclinical animal studies are still not available.