Inhibitor of the transient receptor potential channel TRPC5 with selectivity over other TRCP channels (IC50 values 9.1 µM, 6.4 µM, 1-1.3 µM, 11.3 µM, and 26.5 µM for TRPC3, TRPC4, TRPC5, TRPC6, and TRPC7). Only weakly affected TRPM3 and TRPM8, and TRPV1-4 at markedly higher concentrations of Clemizole. Clemizole was originally developed as antihistaminergic drug and found to inhibit monoamine reuptake in the brain. Clemizole was also found to exhibit antiviral activity by inhibition of NS4B binding to RNA in HCV.