User:Ely.yatun/Brexpiprazole

Pharmacogenomics
One of the main mediators that help metabolize Brexpiprazole is CYP2D6, because of that variation in the gene can cause lower efficacy or higher chance for side effects. Due to this the FDA recommends to adjust the dose based on the activity score of CYP2D6 (can be found with a genetic test).

Based on current evidence ultra-rapid, extensive and intermediate metabolizers do not need a dose adjustment as in all of those cases the concentration of medication in blood is high enough to have good efficacy but also low enough that there is no significant risk for side effects. On the other hand, poor metabolizers have increased risk of experiencing side effects as they do not metabolize the medication fast enough and can reach higher concentration of medication in blood resulting in more side effects, because of that it is suggested to only use half the normal dose. Furthermore, if the patient is taking CYP3A4 Inhibitors/Inducers while being a poor metabolizer it is suggested to take only one quarter of the normal dose.