How quickly a smoker breaks down nicotine could guide about which therapy is best for kicking the habit, according to scientists in the United States and Canada. The authors said, most smokers who try to give up tobacco fail within the first week, therefore matching them to the best treatment is essential. Previous research had established a link between tobacco craving and levels of an enzyme called CYP2A6 which breaks down nicotine. The faster the nicotine metabolism, the likelier it is that the smoker will fail and want to smoke again, and the harder it will be to quit.
1,246 smokers who wanted to quit smoking were part of study. They were randomly assigned to an 11-week course that comprised either a nicotine patch plus a dummy pill, varenicline plus a dummy patch or a dummy patch and a dummy pill. Scientists used a biomarker, the speed at which CYP2A6 does its job, to see whether nicotine patches or a non-nicotine replacement drug called hantix or Champix were more effective. They found that smokers who broke down nicotine quickly, most smokers, in fact were twice as likely to quit if they used varenicline than if they used patches. They also had a better chance of staying off tobacco even six months later. On the contrary, in people who metabolize nicotine slowly it was found that nicotine patches were as effective as varenicline, but without that drug's side effects.
The authors have urged that these results should lead to a simple blood test for nicotine metabolism so that doctors can better advise patients. Prof. Caryn Lerman, professor of psychiatry at the University of Pennsylvania said, "As many as 65 percent of smokers who try to quit relapse within the first week. Matching a treatment based on the rate at which smokers metabolize nicotine could be a viable clinical strategy to help individual smokers choose the cessation method that will work best for them."
The study is published in the journal The Lancet Respiratory Medicine.