The claimed invention relates to the field of biologically active compounds and concerns 2-methylsulphanyl-6-nitro-7-oxo-1,2,4-triazolo[5,1-c][1,2,4]triazinide L-arginine dihydrate, which exhibits an antiviral effect and is intended for the treatment and prophylaxis of human and animal viral diseases, primarily West Nile Virus, and can be used in the chemical and pharmaceutical industry, in scientific research laboratories and medical facilities, and also in veterinary science. The claimed invention is directed toward achieving the technical result of creating a novel effective drug of the azoloazine variety which exhibits antiviral activity toward a group of RNA-containing viruses, and reducing the dependence of the active compound on cell metabolism. This technical result is achieved in the creation of the novel drug 2-methylsulphanyl-6-nitro-7-oxo-1,2,4-triazolo[5,1-c][1,2,4]triazinide L-arginine dihydrate, which exhibits an aniviral effect and has the formula (I). This technical result is achieved in that a method for producing 2-methylsylphanyl-6-nitro-7-oxo-1,2,4-triazolo[5,1-c][1,2,4]triazinide L-arginine dihydrate includes mixing arginine, dissolved in water, and 2-methylthio-6-nitro-7-oxo-1,2,4-triazolo[5,1-c][1,2,4]triazinide sodium dihydrate, dissolved in a (1:1) water-ethanol mixture, whereupon the resultant mixture is boiled then cooled, and the precipitate is filtered off and dried.
