Effects of EPHX1, SCN1A and CYP3A4 genetic polymorphisms on plasma carbamazepine concentrations and pharmacoresistance in Chinese patients with epilepsy.

•The variant EPHX1 c.416A>G genotypes were associated with increased CBZ concentrations in Chinese patients with epilepsy.•The SCN1A IVS5-91G>A or CYP3A4*1G polymorphism was not associated with increased CBZ concentrations in Chinese patients with epilepsy.•There were no associations between all the studied genotypes involving EPHX1 c.337T>C, c.416A>G, SCN1A IVS5-91G>A or CYP3A4*1G and pharmacoresistance in our patient cohort.