Cytochrome P450 2A6
CYP2A6 is the main enzyme that breaks down nicotine. Slow metabolizers keep nicotine in their system longer, smoke fewer cigarettes per day, and have a lower lifetime lung cancer risk. Their response to smoking cessation also differs: nicotine replacement works better for slow metabolizers, while fast metabolizers tend to benefit more from varenicline or bupropion.
Gene2Rx reports your CYP2A6 genotype across 7 named star alleles, built from 10 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 CYP2A6 allele in the PharmVar catalog.
Gene2Rx covers 1 medication with published pharmacogenetic guidance for CYP2A6, drawn from CPIC and FDA sources. Each drug links to its full pharmacogenetics page.
This page lists drugs affected by CYP2A6. 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 CYP2A6 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.