The new drug, varenicline or Chantix promises to be more effective than bupropion or Zyban in helping smokers kick the habit In addition it has also shown to promote longer-lasting abstinence according to the results of three studies published in the Journal of the American Medical Association this week.
Chantix is the first anti-smoking prescription drug in over a decade. It works by stimulating sufficient dopamine release to curb cravings and at the same time blocks the reinforcing effects of smoked nicotine.
The drug is marketed by Pfizer Inc. and received FDA approval in May.
A related editorial however cautions smokers against considering the drug as a panacea for quitting smoking. According to co-author Dr. Robert C. Klesges, from the University of Tennessee in Memphis, "There are some important gastrointestinal side effects and, in the current studies, most people given the drug actually did not quit smoking".
Dr. Karen R. Reeves, from Pfizer Global Research and Development in Groton, Connecticut, and colleagues compared the effects of Chantix against those of Zyban and placebo in two Pfizer-sponsored studies. In a third study, Chantix was tested against placebo in maintaining abstinence from smoking.
The first study involved 1025 people who smoked at least 10 cigarettes per day. After 12 weeks of Chantix an immediate abstinence rate of 44 percent was noted in these people, which was significantly higher than the 29.5 percent and 17.7 percent rates achieved with Zyban and placebo, respectively.
It was noted however that at 1 year the abstinence rate for Chantix was not much different from that of Zyban: 21.9 percent vs. 16.1 percent although it was higher than the 8.4 percent seen with the placebo.
Several patients also reported nausea as a side effect of Chantix while Zyban was associated with a high rate of insomnia.
The second study showed a higher abstinence rate at 1 year of about 23 percent with Chantix compared to 14.6 percent with Zyban. 30 percent of the patients, however, did report nausea with Chantix.
In the third study 1210 smokers were involved who remained abstinent for at least 7 days after completing a 12-week course of Chantix. The subjects were randomized to continue the drug for an additional 12 weeks or switch to placebo.
It was found that subjects who remained on Chantix had a continuous abstinence rate from weeks 13 to 52 of 43.6 percent, which was higher than the 36.9 percent rate seen in the placebo group.
According to Klesges although the results are encouraging smokers should not get caught up in the media hype likely to surround this new drug and think that it represents any easy cure for their problem. "There is no such thing as a magic bullet for any condition, let alone one that involves complex human behavior."
Still, as Klesges noted, 'This drug may be as good as we're going to get in terms of a medical therapy for smoking cessation. There clearly is an addictive component to smoking and the best results are achieved when a medical therapy is combined with a behavioral intervention.'