Pharmacogenetics can boost your chance of quitting smoking

Pharmacogenetics can boost your chance of quitting smoking

The decision to quit smoking is a big step to improving your health. It is never too late to quit and the benefits include a reduction in cancer, heart and lung disease, and improved quality of life.

When attempting to quit smoking, both counseling and smoking cessation medications can increase your chances of successfully quitting.

The most common medications used to help people quit smoking include nicotine replacement therapy (for example, nicotine patches, gum, lozenges, inhalers, and sprays), bupropion (Zyban), and varenicline (Champix). These medications can reduce cravings and nicotine withdrawal symptoms, but can also cause side effects for some people.

To ensure these medications will be safe and effective for each patient, it is important to take into account not only the patient’s drug history, medical history, and current medications but also the patient’s unique genetic makeup.

Genetic testing can help predict whether people may have a better or worse than predicted response to medications for smoking cessation

For patients who are CYP2A6 normal or ultrarapid metabolizers, varenicline may be more likely to help quit and maintain a smoke-free lifestyle at six months compared to nicotine replacement therapy. Alternatively, CYP2A6 intermediate or poor metabolizers may be more likely to experience side effects from varenicline such as nausea and abnormal dreams [1]. CYP2A6 intermediate or poor metabolizers may also benefit from extended therapy with nicotine replacement therapy compared to stopping after eight weeks [2].

Genetics also affects bupropion response when using it to help quit smoking. The results of a pooled analysis of two clinical trials suggest that genetic variants in the ANKK1 gene (rs1800497) influence response to bupropion for smoking cessation. Patients with the GG genotype who are treated with bupropion may be more likely to quit smoking as compared to patients with the AA or AG genotypes [3]. The rs1808682 SNP is also associated with bupropion response: patients with AA or AG genotypes may have an increased response to bupropion for smoking cessation [4].

Personalizing smoking cessation treatment with TreatGxPlus

TreatGxPlus offers pharmacogenetic testing and a decision support tool that helps tailor medications to the patient’s unique genetic makeup and health profile. TreatGxPlus detects interactions between medications, genetics and health information to minimize drug-related side effects and increase the likelihood of selecting an effective medication.

In smoking cessation, the TreatGx decision support tool generates personalized medication options based on high-level evidence as well as the patient’s drug history, medical history, current medications and genetic variants. All the results from the TreatGxPlus pharmacogenetic report are automatically uploaded into the TreatGx decision support tool and are ready to use. The medication options include individualized dose and approximate drug cost relative to other drugs shown.



In Canada, TreatGxPlus is brought to you in partnership with LifeLabs


1. Lerman C, et al. Use of the nicotine metabolite ratio as a genetically informed biomarker of response to nicotine patch or varenicline for smoking cessation. Available at:
2. Lerman C, et al. Genetic variation in nicotine metabolism predicts the efficacy of extended-duration transdermal nicotine therapy. Available at:
3. David SP, et al. Bupropion efficacy for smoking cessation is influenced by the DRD2 Taq1A polymorphism: analysis of pooled data from two clinical trials. Available at:
4. King, D. P. et al. Smoking Cessation Pharmacogenetics: Analysis of Varenicline and Bupropion in Placebo-Controlled Clinical Trials. Neuropsychopharmacology 37, 641 (2012).

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