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Cytochrome P450 2D6

Published: October 2013

Hot Topic Q&A is an opportunity for viewers to submit questions to the Hot Topic presenter. The opportunity to submit questions for this topic is now closed.

The following questions were submitted by viewers and answered by the presenter, John Logan Black, MD, Co-director of the Personalized Genomics Laboratory, Consultant in the Department of Laboratory Medicine and Pathology, and Professor in the College of Medicine

Questions are presented as submitted (unedited).

  1. Is it realistic to perform cytochrome testing for all therapeutic drugs?

    No, not yet. There are 30 cytochrome P450 enzymes. Several of them metabolize drugs and no lab can genotype for all of them yet. When whole genome sequencing becomes available, these will be genotyped but then the issue will be that almost nobody understands these genes well enough to interpret full genome data. We are working on this problem, however.

  2. What is the full range/number of pharmaceuticals covered by the cascade testing?

    The cascade testing is specific for CYP2D6. So, you are asking what drugs are metabolites of CYP2D6. No source of information is complete but I will give you a webpage to look at which will help you know which drugs are CYP2D6 substrates. This webpage is published by Indiana University. View the webpage here. Several enzymes are listed. Look under substrates 2D6 and you will find several commonly used drugs that are substrates. If you look further you will also find lists of CYP2D6 enzyme inhibitors and inducers.