Tizoxanide is the active metabolite of Nitazoxanide, which is a thiazolide anti-infective compound against anaerobic bacteria, protozoa, and a range of viruses. Tizoxanide has anti-HIV-1 activities. IC50 value: Target: Antiviral agent in vitro: Tizoxanide inhibited virus replication of all CIVs with 50% and 90% inhibitory concentrations ranging from 0.17 to 0.21 μM and from 0.60 to 0.76 μM, respectively [2]. Nitazoxanide and its primary metabolite, tizoxanide, inhibit hepatitis C virus (HCV) replication in HCV replicon systems. Interestingly, serial passage in nitazoxanide or tizoxanide resulted in increased sensitivity to alpha interferon 2b: EC(50)s and EC(90)s were reduced three- and eightfold, respectively [3].