Although smoking rates in the United States have declined dramatically since their peak in the 1960s, 42 million Americans, including teenagers and young adults, still have trouble kicking their nicotine habit. A recent study conducted by researchers from the Perelman School of Medicine at the University of Pennsylvania has revealed that the manner in which a smoker metabolizes nicotine in his body after quitting could decide if the pill or the patch works best for smoking cessation.

"This is a much-needed, genetically-informed biomarker that could be translated into clinical practice," Dr. Caryn Lerman, a professor of Psychiatry and director of the Center for Interdisciplinary Research on Nicotine Addiction, said in a statement. "Matching a treatment choice based on the rate at which smokers metabolize nicotine could be a viable strategy to help guide choices for smokers and ultimately improve quit rates." Lerman also serves as the deputy director of the Abramson Cancer Center.

Lerman and her colleagues recruited 1,246 treatment-seeking smokers who over the course of 11 weeks either received a nicotine patch and a placebo pill, the drug varenicline (marketed as Chantix) and a placebo patch, or a placebo patch and a placebo pill. Participants were categorized as either slow metabolizers or normal metabolizers before having their blood tested within seven days of beginning treatment to measure their nicotine to metabolite ratio.

After assessing each smokers’ behavior to determine abstinence as well as conducting follow-ups at six and 12 months, researchers found that close to 40 percent of normal metabolizers taking varenicline were able to abstain from nicotine use by the end of treatment compared to those on the nicotine patch. Although the ability to quit smoking using the patch or the pill was equal in slow metabolizers, there were more side effects associated with varenicline.

"Our data suggest that treating normal metabolizers with varenicline, and slow metabolizers with the nicotine patch could provide a practical clinical approach," the authors explained. "What's more, extending the duration of these treatments (beyond 11 weeks) could potentially sustain the benefit of tailored treatment."

Approximately 70 percent of smokers who try to quit end up relapsing within the first week. Considering six million people around the world die each day as the result of a smoking-related illness and tobacco-related health care costs have reached $200 billion, the research team said the importance of smoking cessation cannot be understated.

"These findings not only support the use of the nicotine metabolite ratio as a biomarker to guide treatment choices," Lerman added, "but also underscore the notion that tobacco dependence is a heterogeneous condition and that smoking cessation treatments are not equally effective for all smokers."

According to the American Cancer Society, nicotine is a drug found naturally in tobacco that is just as addictive as heroin or cocaine. Smokers addicted to nicotine developed both physical and emotional dependencies. Similar research has found that smokers who can fight the urge to smoke for seven days have a better chance of staying cigarette-free for six months.

Source: Hawk L, Schnoll R, 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: a randomised, double-blind placebo-controlled trial. The Lancet Respiratory Medicine. 2015.