Clemizole

Description: Clemizole (also known as AL 20, P 48, and/or Reactrol), is a potent inhibitor of transient receptor potential channel TRPC5 (Canonical transient receptor potential channel 5) and also an H1 histamine receptor antagonist. It is found to substantially inhibit HCV replication. The IC50 of Clemizole for RNA binding by NS4B is 24+/-1 nM, whereas its EC50 for viral replication is 8 uM. Clemizole efficiently blocks TRPC5 currents and Ca(2+) entry in the low micromolar range (IC50 = 1.0-1.3 uM). Clemizole was not only effective in blocking heterologously expressed TRPC5 homomers but also TRPC1:TRPC5 heteromers as well as native TRPC5-like currents in the U-87 glioblastoma cell line.

References: Nat Biotechnol. 2008 Sep; 26(9):1019-27; Mol Pharmacol. 2014 Nov; 86(5):514-21.