Pyrazofurin is an antitumor pyrimidine nucleoside analogue and a orotate-phosphoribosyltransferase inhibitor. Pyrazofurin inhibits cell proliferation and intracellular DNA synthesis by inhibiting uridine 5-phosphate synthase. Pyrazofurin is also an antibiotic with a broad spectrum of antiviral activity[1][2][3][4].