In vitro data fra humane levermikrosomer indikerer at cytokrom P450 enzymerne CYP2D6 og CYP1A2 er involveret i dannelsen af 8- hydroxy metabolitten af mirtazapin, og at CYP3A4 er ansvarlig for dannelsen af N- demethyl og N- oxid metabolitterne.
In vitro data from human liver microsomes indicate that cytochrome P450 enzymes CYP2D6 and CYP1A2 are involved in the formation of the 8-hydroxy metabolite of mirtazapine, whereas CYP3A4 is considered to be responsible for the formation of the N-demethyl and N-oxide metabolites.