(around 71%) have the functional group of CYP2D6 alleles, while functional alleles represent only around 50% of the allele frequency in populations of Asian descent. This variability is accounted for by the differences in the prevalence of various CYP2D6 alleles among the populations–approximately 10% of whites are intermediate metabolizers, due to decreased CYP2D6 function, because they appear to have the non-functional CYP2D6*4 allele, while approximately 50% of Asians possess the decreased functioning CYP2D6*10 allele. Ligands Following is a table of selected substrates, inducers and inhibitors of CYP2D6. Where classes of agents are listed, there may be exceptions within the class. Inhibitors of CYP2D6 can be classified by their potency, such as: Strong inhibitor being one that causes at least a 5-fold increase in the plasma AUC values of sensitive substrates metabolized through CYP2D6, or more than 80% decrease in clearance thereof. Moderate inhibitor being one that causes at least a 2-fold increase in the plasma AUC values of sensitive substrates metabolized through CYP2D6, or 50-80% decrease in clearance thereof. Weak inhibitor being one that causes at least a 1.25-fold but less than 2-fold increase in the plasma AUC values of sensitive substrates metabolized through CYP2D6, or 20-50% decrease in clearance thereof. Dopamine biosynthesis References Further reading External links Flockhart Lab Cyp2D6 Substrates Page at IUPUI PharmGKB: Annotated PGx Gene Information for CYP2D6 2 EC 1.14.14 Amphetamine