The overexpression of ATP-binding cassette sub-family B member 1 (ABCB1; MDR1; P-glycoprotein 170) and breast cancer resistance protein (BCRP; ABCG2), major human efflux transporters for LTG at the blood–brain barrier, have been shown to be important mechanisms of pharmacoresistance in patients with epilepsy (Romermann et al., 2015). This evidence concerns the gene ABCG2 and epilepsy.