An antidepressant drug delivered through a patch on the skin is no better than placebo for helping smokers kick the habit, new research shows.

Eldepryl (generic name selegiline) is used to treat Parkinson’s disease, depression, and dementia, in both pill and patch form. Nicotine craving is a major hurdle for smokers trying to abstain, and selegiline can help maintain levels of brain chemicals like dopamine that are reduced in the absence of nicotine.

“That’s why we hoped that selegiline might reduce the cravings and urges associated with quitting and thus help make it easier to quit,” Dr. Joel D. Killen of Stanford University School of Medicine in Palo Alto, California, one of the researchers who conducted the study, told Reuters Health.

Two previous studies using selegiline in pill form suggested the drug could reduce cravings in smokers trying to quit.

To investigate further, Killen and his colleagues randomly assigned 243 adult smokers to a patch containing selegiline or to a placebo patch. The study participants were instructed to begin using the patch on the day that they planned to quit smoking, and to continue to use one patch every 24 hours for the next eight weeks. All of the study participants also met with trained staff at a community smoking-cessation clinic to develop skills to help them continue to abstain from smoking.

At the end of eight weeks, 26 percent of the patients in the selegiline group had been abstinent for at least the past week, as measured by carbon monoxide breath tests, while nearly 30 percent of the placebo group had been abstinent for the same period. At 25 weeks, 17 percent of the selegiline group and 19 percent of the placebo group were abstinent; at 52 weeks, around 20 percent of people in both groups were abstinent.

The researchers did find gender differences in quitting success; 28 percent of women were abstinent at 52 weeks, compared to 16 percent of men.

There was also some evidence that study participants who scored high on a test of “behavioral activation” - meaning they had a strong response to rewarding stimuli, such as cigarettes for smokers - did better with selegiline. This effect would make sense, the authors note, because dopamine promotes sensations of reward in the brain, and selegiline facilitates dopamine’s brain activity, so smokers more sensitive to dopamine-mediated reward might be more responsive to the drug.

However, the behavioral therapy administered along with the patches seemed to be the most effective treatment of all, the researchers note.

“Smokers in the placebo group did better than expected, and we think that the psychological treatment provided may have contributed to this result,” Killen said via e-mail. “We would emphasize that successful smoking cessation treatments require both behavioral and pharmacologic components.”

Twenty-one percent of U.S. adults - about 46 million people - smoke, according to the Centers for Disease Control and Prevention. Often multiple attempts are needed before a smoker quits successfully.

SOURCE:  Addiction, September 2010.