What is CYP2D6?

Updated: Feb 03, 2021
  • Author: Ali Torkamani, PhD; Chief Editor: Keith K Vaux, MD  more...
  • Print


CYP2D6 is a member of the cytochrome P450 family of enzymes involved in the oxidative metabolism of drugs. CYP2D6 is among the most promiscuous of these enzymes, involved in the metabolism of approximately 20% of drugs in clinical use, and displays large individual-to-individual variability in activity due to genetic polymorphisms. [2] The oxidative metabolism of most approved SSRIs is executed, in part, by CYP2D6. [3, 4, 5, 6]

Pharmacogenetic testing is being evaluated for routine implementation, and it has been reported that over 90% of the population has at least one actionable genetic variant. These genetic variants can affect the safety and efficacy of certain drugs. Genetic polymorphisms of CYP2D6 have been shown to affect response to tamoxifen, opioid analgesics, antidepressants, and antipsychotics, for example. [3, 4, 5, 6]

Patients are classified into the following 4 categories of CYP2D6 activity, from highest to lowest functioning: ultrarapid metabolizer (UM); extensive, or normal, metabolizer (EM); intermediate metabolizer (IM); and poor metabolizer (PM). Tables for the conversion of star allele diplotypes to these metabolizer categories were updated in October 2019 and are available at the CPIC website. [7]

Did this answer your question?
Additional feedback? (Optional)
Thank you for your feedback!