Pharmacology

FAVIDOSE trial is a Phase I randomized, double blind controlled, monocentric, dose escalation clinical trial. The primary purpose of this trial is to evaluate tolerance of high doses of favipiravir for 14 days in healthy volunteers. This trial also looks to characterize favipiravir pharmacokinetics in blood and favipiravir levels in sperm. A pharmacogenetics analysis will be conducted in an attempt to identify genetic variants of metabolism and transport enzymes of favipiravir to explain the inter-individual variability of pharmacokinetic parameters of favipiravir. Three sequential dose levels including distinctive participants: * level 1: D1: 2400 mg BID; D2 to D13: 1600 mg BID and D14: 1600 mg in the morning; * level 2: D1: 2400 mg BID; D2 to D13: 2000 mg BID and D14: 2000 mg in the morning; * level 3: D1: 2400 mg BID; D2 to D13: 2400 mg BID andD14: 2400 mg in the morning. Three study groups of maximum of 8 participants, 6 receiving favipiravir and 2 receiving placebo per dose level, three dose levels proposed. Seven additional participants with the same follow up will be included and randomized (6:1 ratio) at the maximum tolerated dose level to allow a satisfactory accurate characterization of pharmacokinetics and pharmacogenetics of favipiravir and their determinants (maximum 39 participants in total, taking into account 8 participants - 2 per dose level - replaced because loss of follow-up before the end of treatment).