Cytochrome P450 2D6
CYP2D6 is the most clinically important pharmacogene.[1] It metabolizes around a quarter of all prescription drugs, including many antidepressants, opioids, and stimulants.[2] The gene is unusually variable: roughly 7 percent of people are poor metabolizers (they barely activate CYP2D6), and another 1 to 3 percent are ultrarapid metabolizers (their enzyme is overactive).[3]
Gene2Rx reports your CYP2D6 genotype across 147 named star alleles, built from 123 variants curated by PharmVar.
Star alleles (like *1, *2, *4) are standardized names for distinct versions of a pharmacogene. *1 is the reference; higher numbers identify variants discovered later that change the enzyme's activity.
You inherit one allele from each parent, so your genotype is a pair (e.g. *1/*4). The pair determines your predicted phenotype — for example, whether you metabolize a drug at a normal, decreased, or no-function rate.
PharmVar is the international registry that defines and curates these allele names. Gene2Rx tests the variants required to call every CYP2D6 allele in the PharmVar catalog.
Gene2Rx covers 45 medications with published pharmacogenetic guidance for CYP2D6, drawn from CPIC and FDA sources. Each drug links to its full pharmacogenetics page.
These branded medications include at least one active ingredient whose metabolism or action involves CYP2D6. Each links to its full pharmacogenetic breakdown.
This page lists drugs affected by CYP2D6. A Gene2Rx report tells you which metabolizer group you fall into, and what that means for every medication on this list.
Get your report Look up a medicationInformational only, not medical advice. The presence of a CYP2D6 pharmacogenetic guideline does not mean every patient needs to change their dose. Never start, stop, or change a medication without talking to your prescribing clinician.