April 17, 2013
Varenicline Appears Most Effective Among
Smoking-Cessation Therapies

Houston—The drug varenicline, marketed as Chantix in the United States, appears to be more effective for smoking cessation than some other commonly used drugs or involvement in an unmedicated assisted smoking-cessation program, according to a recent study.

For the study, published recently in the journal JAMA Psychiatry, MD Anderson Cancer Center researchers compared the relative efficacy of varenicline and bupropion—both widely used antismoking drugs—as well as intensive counseling to determine the effect on emotional functioning and success at smoking cessation.

Bupropion compounds are marketed under a variety of names in the United States, including Wellbutrin and Zyban.

“National surveys show that about 20% of adults continue to smoke, but it’s disproportionally high among people in low socioeconomic populations and those with mental illness,” said Paul Cinciripini, PhD, professor in the Department of Behavioral Science. “When smokers try to quit, many are likely to experience a range of nicotine withdrawal symptoms, including negative mood, difficulty concentrating, irritability and even depressive symptoms making quitting difficult and increases the chances of relapse.”

In this study, funded by the National Institute on Drug Abuse, scientists examined data from 294 smokers who were trying to quit, randomizing them into one of three groups: varenicline, bupropion, or placebo. Participants were assessed throughout the 12-week medication portion of the program and also 3 and 6 months after quitting.

Using four different measurements of abstinence, researchers found that only varenicline significantly improved abstinence rates by all measures at all time periods compared with placebo. They also found that varenicline consistently outperformed buproprion, but, unlike the placebo comparisons, that finding did not reach statistical significance because of small sample size.

“Our findings suggest that smokers trying to quit will have a better experience with varenicline as opposed to trying to quit on their own or by taking bupropion,” Cinciripini said. “The more we can reduce these negative symptoms associated with quitting, the better experience of the smoker and this may mean that even if they don't quit this time, they will be encouraged to try again.”

For the study, researchers looked at the effects of medication alone, abstinence alone, and the combination of the two on depression, negative affect, and other symptoms of nicotine withdrawal, including craving.

While smoking abstainers using either bupropion or varenicline generally experienced lower levels of sadness, the varenicline group did much better in terms of overall depressive symptoms—whether with smoking abstainers or nonabstainers.

“This is especially intriguing given the post-marketing data with varenicline that suggests that it may worsen depressive symptoms,” said Cinciripini. “More research is needed to look carefully at smokers with current psychiatric illness taking varenicline, since they were not included in this research study.”

Varenicline also was found to produce lower levels of craving, even among those who did not fully quit smoking, and to reduce the psychological reward received from smoking.

“In a community sample, varenicline exerts a robust and favorable effect on smoking cessation relative to placebo and may have a favorable (suppressive) effect on symptoms of depression and other affective measures, with no clear unfavorable effect on neuropsychiatric adverse events,” according to the authors.

Cinciripini added that “it is evident from the findings that varenicline is hitting many more affective targets, in comparison to bupropion or placebo, and there is a distinct benefit of these effects on cessation even among those who do not fully abstain.”

U.S. Pharmacist Social Connect