Selective serotonin reuptake inhibitors (SSRIs) are used for the treatment of major depressive and anxiety disorders, and may be used to treat other psychiatric conditions. Paroxetine is extensively metabolized by cytochrome P450 2D6 (CYP2D6) and variations in CYP2D6 may affect drug exposure. CYP2D6 ultrarapid metabolizers might have lower or undetectable paroxetine plasma concentrations while CYP2D6 poor metabolizers showed greater drug exposure to paroxetine compared to extensive metabolizers at similar drug doses. Therapeutic guidelines for the SSRI paroxetine based on CYP2D6 genotype have been published in Clinical Pharmacology and Therapeutics by the Clinical Pharmacogenetics Implementation Consortium (CPIC) and are available on the PharmGKB website. [from
PharmGKB]