Raw research findings for this medication. Mostly single studies, not curated or confirmed robust.
Varenicline is a stop-smoking medicine that partly activates the alpha4-beta2 nicotinic receptors in the brain: it eases craving and withdrawal while blocking nicotine from giving its usual reward. It is taken for around twelve weeks, starting a week or so before the quit date. It is sold as Chantix and Champix.
Varenicline is cleared almost entirely unchanged by the kidneys, so drug-processing genes play little part. Studies have looked at the nicotinic receptor genes it acts on and near (CHRNA4, CHRNB2, CHRNA5, CHRNA3), and at CYP2A6, which sets how fast a person clears nicotine and has been linked to which stop-smoking treatment works better. The findings come from a few studies, and there is no CPIC or DPWG guideline.
Every published finding on gene variants and Chantix. Upload your DNA file to see which of these rows apply to you.
PharmGKB weighs all studies of a variant and rates how strong the evidence is, from 1A (strongest) to 4.
CHRNA5 rs16969968: Level 3. Efficacy: Tobacco Use Disorder. 7.
CHRNA5 rs588765: Level 3. Efficacy: Tobacco Use Disorder. 2.
CHRNA5 rs503464: Level 3. Efficacy, Toxicity: Tobacco Use Disorder. 1.
HYKK rs7164594: Level 3. Efficacy: Tobacco Use Disorder. 1.
Studies of how well it worked in people carrying a variant.
Study findings and evidence levels: PharmGKB (CC BY-SA 4.0). Guidelines: CPIC and DPWG, as bundled in PharmCAT. Most studies were done mainly in people of European ancestry.
More drugs from the same category
Smoking Cessation (class) (Smoking Cessation Agents)
Not a prescribing recommendation. This page is educational information about pharmacogenomic research and clinical guidelines - it is not medical or dosing advice, and not a prediction of how any medication will work for you. Never start, stop, or change a medication or dose based on it; talk to your doctor or pharmacist, who can order clinical-grade testing if appropriate.
Content updated September 2026.
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