MAOA and migraine disorder: At support of the heterogeneity in hepatic metabolism, likely due to MAO-A and CYP1A2, in different studies conducted on in migraine patients outside attacks, during attack and in healthy volunteers significant inter-individual variability was observed in the measured plasma levels of different triptans in different situations such as Cmax after oral administration of Sumatriptan [36] (metabolised by MAO-A), rather than 2 h after the administration of Zolmitriptan [37] (metabolised by CYP1A2 and MAO-A) [Fig. 4].