Nashville, TN—Which product is better for patients seeking smoking cessation: varenicline or a nicotine patch?

Getting the answer might be as easy as performing a blood test, according to a new study published in the journal Nicotine & Tobacco Research. The key, Vanderbilt University Medical Center researchers explain, is determining whether the patient metabolizes nicotine normally or slower than normal.

Study authors pointed to a large study in 2015 that suggested that normal metabolizers of nicotine would be able to double their smoking-cessation success by using varenicline—marketed as Chantix—instead of a nicotine patch, but that the product selected didn’t make much difference for slow metabolizers. Those results have not yet been widely used in clinical practice, but the Vanderbilt researchers employed the information to better personalize stop-smoking treatment.

“You have to treat about five normal metabolizers with varenicline to help one person quit smoking, while, by contrast, you have to treat about 26 normal metabolizers with the nicotine patch in order to help just one quit smoking,” pointed out lead author Quinn Wells, MD, Assistant Professor of Cardiovascular Medicine. 

He and the other researchers posited that metabolism-informed care (MIC) could improve outcomes by matching normal metabolizers with nonnicotine medication such as varenicline while prescribing nicotine replacement therapy (NRT), which is less expensive and has fewer side effects, to the slow metabolizers.

To determine that, a feasibility randomized, controlled trial of MIC versus guideline-based care (GBC) was conducted with 81 outpatient adult daily smokers with medical comorbidity. Nicotine metabolite ratio (NMR) was determined for all participants, who had a median age of 53 years and were 46% female. An NMR result of ≥0.31 was considered normal and <0.31 was determined to be slow.

The primary outcome was feasibility of MIC, including match rates between that and the medications. Assessed over the next 6 months were secondary endpoints including cessation confidence, medication use, and smoking status.

Results indicated that, despite high varenicline prescription rates of around 60% in both arms, NMR-medication matching was higher in MIC (84%) versus GBC (58%) participants, for an unadjusted odds ratio (OR) of 3.67. Little difference was detected with secondary endpoints, however.

The study authors reported that more MIC participants—84%—were prescribed NMR-matched medications, whereby normal metabolizers received varenicline and slow metabolizers received the NRT patches, compared with GBC participants—58%. Noting that the number needed to treat to aid smoking cessation in one normal metabolizer is only 4.9 for varenicline versus 26 for the patch, the researchers suggested that wide implementation of MIC could both improve drug efficacy in normal metabolizers and minimize side effects in slow metabolizers.

“MIC, an NMR-based precision approach to smoking cessation, was acceptable to 90% of smokers and improved NMR-medication match rates more than three-fold compared to GBC, even with generally high use of varenicline,” the researchers conclude. “These data support the feasibility of MIC, which could maximize efficacy of smoking cessation medication while minimizing side effects and cost.”
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