New anti-smoking drug Varenicline (Chantix) promotes longer-lasting abstinence

Scientists have found that a new anti-smoking drug may be more effective than drugs currently in use to help smokers kick the habit and it has the added advantage of promoting longer-lasting abstinence.

Although nearly 41 percent of smokers try to quit smoking each year, relapse is more than common, and only about 10 percent achieve and maintain abstinence mainly because of the negative effects of nicotine withdrawal.

Therapies to treat nicotine dependence such as nicotine replacement therapy and bupropion (Zyban), have been seen to be only moderately effective and there is a need for more effective therapies.

Varenicline (Chantix) is a non-nicotine drug that is thought to be beneficial for smoking cessation by stimulating the release of the chemical dopamine in the brain to reduce craving and withdrawal while simultaneously blocking the reinforcing effects of smoked nicotine.

Most other smoking cessation pharmacotherapies are nicotine replacement products.

Chantix is the first prescription anti-smoking drug in over a decade, is marketed by Pfizer and received FDA approval in May.

Dr. David Gonzales of Oregon Health & Science University, Portland, and colleagues conducted three studies to assess the effectiveness of Chantix when compared to Zyban and a placebo.

The first trials were conducted at 19 U.S. centers from June 2003 to April 2005 and 1025 participants were randomly assigned to receive brief counseling plus either Chantix twice a day, or Zyban twice a day, or a placebo, orally for 12 weeks, with 40 weeks of nondrug follow-up.

The study found that 12 weeks of Chantix was associated with an immediate abstinence rate of 44 percent, significantly higher than the 29.5 percent and 17.7 percent rates achieved with Zyban and placebo, respectively.

In another study, Dr. Douglas E. Jorenby of the University of Wisconsin School of Medicine and Public Health and colleagues conducted an identical study of 1,027 adult smokers at 14 research centers between June 2003 and March 2005.

The participants were randomized to the same drug regime plus weekly brief smoking cessation counseling.

The researchers found that at the end of the treatment period, the odds of quitting smoking with Chantix were significantly greater than the odds of quitting with either placebo or Zyban.

In the third study, by Dr. Serena Tonstad of Ulleval University Hospital, Oslo, Norway and colleagues conducted at medical clinics in 7 countries with follow-up a year later, 1,927 cigarette smokers were treated for 12 weeks with Chantix twice a day, 1,236 or a placebo.

The continuous abstinence rate was again higher for the Chantix group than for the placebo group.

The results of the three studies suggest that Chantix when it comes to preventing a relapse represents an important new development.

Good though the results appear to be co-author Dr. Robert C. Klesges, from the University of Tennessee, warns that Chantix does produce gastrointestinal side effects such as nausea and is not a guarantee that a person will quit smoking.

Klesges says it is clear that the best results are achieved when a medical therapy is combined with a behavioral intervention.

The research is published in the Journal of the American Medical Association July 5, 2006.