Chlormethiazole is an potent and orally active GABAA agonist[1]. Chlormethiazole inhibits cytochrome P450 isoforms: CYP2A6 and CYP2E1 in human liver microsomes. Chlormethiazole is an anticonvulsant agent and has the potential for treating convulsive status epilepticus[2].
Clomethiazole (1 mM), in the absence of GABA, to α1/β1/γ2 or α1/β2/γ2 subunit-containing cells produced large whole-cell currents[1].Clomethiazole activate GABAA currents in α1/β1/γ2- and α1/β2/γ2-containing cells, with EC50 values of 0.3 and 1.5 mM, respectively[1].Clomethiazole (30 μM) at low concentration also potentiates the action of GABA in both cell types, equivalent to a 3-fold increase in potency and up to 1.8-fold increase in maximal current[1].Clomethiazole inhibits cytochrome P450 isoforms, CYP2A6 and CYP2E1 with IC50 values of 24 µM and 42 µM, respectively, in human liver microsomes, meanwhile all other isoforms exhibiting values > 300 µM[2].
[1]. Nelson RM, et al.Electrophysiological actions of gamma-aminobutyric acid and clomethiazole on recombinant GABA(A) receptors.Eur J Pharmacol. 2002 Oct 11;452(3):255-62. [2]. Stresser DM, et al. Selective Time- and NADPH-Dependent Inhibition of Human CYP2E1 by Clomethiazole.Drug Metab Dispos. 2016 Aug;44(8):1424-30