A daily dose of 40 mg may be considered for some patients based on tolerability, including those who are known CYP 2D6
poor metabolizers, and those taking strong CYP2D6 inhibitors.
18) The patient used finasteride, amlodipine, atorvastatin, and bicalutamide, which are CYP 3A4 inhibitors and substrate, and metoprolol, a CYP 2D6
substrate and minor inhibitor.
4,8,12,13] Six major classes of CYP isoenzymes that play a vital role in drug biotransformation are CYP 1A2, CYP 2C19, CYP 2C9, CYP 2D6
, CYP 2E1, and CYP 3A4.
The CYP 2D6
activity score: translating genotype information into a qualitative measure of phenotype.
In those individuals with the poor metabolizer phenotype for CYP 2D6
, codeine causes only nausea and vomiting and has no analgesic effects.
After statistical adjustment for age, socioeconomic status, comorbidity, use of other CYP 2D6
drugs, and timing and duration of tamoxifen therapy, investigators found that the breast cancer mortality risk was increased 24% among women who were coprescribed paroxetine during 25% of their tamoxifen treatment.
Fluoxetine is also a potent inhibitor of CYP 2D6
, but was not shown to increase breast cancer mortality in the study, said Dr.
Fluoxetine, fluvoxamine, and paroxetine are the SSRIs with the greatest likelihood of having a significant CYP 450 interaction by inhibiting the metabolism of medications mediated by CYP 2D6
, CYP 1A2, and CYP 2C19.
Using the CYP 2D6
enzyme, the liver metabolizes risperidone via the hydroxylation metabolic pathway by changing risperidone to its major metabolite, 9-hydrorisperidone.
These markers have been a reliable guide for treatment and predictor of breast cancer outcomes; however, several emerging biomarkers, such as the CYP 2D6
genotype to determine tamoxifen (Soltamox([TM]), AstraZeneca Pharmaceuticals, LP) efficacy, are also being researched extensively.
9% Olanzapine levels increased because of loss of interaction between metoprolol, a CYP 2D6
substrate, and olanzapine 24% Rebound from abrupt discontinuation of the beta blocker is causing extrapyramidal symptoms and akathisia 42% Olanzapine levels increased after he stopped taking omeprazole, a potent CYP 1A2 inhibitor 25% Olanzapine levels increased because greater stomach acidity enhanced absorption following discontinuation of the proton pump inhibitor * Data obtained via CurrentPsychiatry.
In poor CYP 2D6
metabolizers, the effect of pesticides was increased twofold.