• Unlike most other CYP450 enzymes, CYP2D6 is not very susceptible to enzyme induction. Therefore, genetics, rather than drug therapy, accounts for most ultra-rapid CYP2D6 metabolizers.
• When using multiple medications that are substrates and/or inhibitors of CYP2D6, genotyping may not reflect the true prevalence of the CYP2D6 poor metabolizer phenotype.
• The activity of CYP1A2 alleles is largely determined by environmental factors and genetic variability.
Making sense of CYP2D6 and CYP1A2genotype vs phenotype
