14 DAY TRIAL // Ten years have passed since the last anti-smoking drug was released on the market but now a new one, named varenicline, has been licensed for use and seems to be even more promising.
The new drug could increase three times the odds of a person renouncing smoking. This new drug exploits the fact that nicotine provokes addiction by stimulating receptors in the nervous system that expel dopamine, the "happiness" hormone. Varenicline attacks these receptors, triggering a low-level dopamine release, which decreases craving symptoms. The new drug also impedes the receptors to absorb nicotine, rendering continued smoking less satisfying; the smoker's desire for smoking is cut off, enabling him to quit easily.
Cochrane researchers investigated varenicline's effects on 2451 people on varenicline and used 2473 placebo volunteers. Varenicline determined a three times higher quitting level for 12 months or longer by comparison to placebo subjects. Varenicline proved also 1.5 times more effective than bupropion, an older antismoking drug and an antidepressant drug. "What we need now are some trials that make direct comparisons between varenicline and nicotine replacement therapy" says Lead Review Author Kate Cahill, who works in the Department of Primary Health Care at Oxford University.
Indeed, antidepressants bupropion (Zyban) and nortriptyline double a person's odds of getting rid of this harmful addiction and have few side-effects, but selective serotonin reuptake inhibitors (SSRIs) like fluoxetine (Prozac) are not effective.
This connection makes sense, as people suffering from depression present low levels of dopamine in their brains and stopping smoking can provoke depressive symptoms in some smokers.
By now, many trials revealed that bupropion and nortriptyline are effective, while SSRIs have no effect. "Since bupropion and nortriptyline appear to work as well in non-depressed as depressed persons, this suggests they help smokers quit in some way other than as antidepressants," says John Hughes, a Professor in the Department of Psychiatry at the University of Vermont, Burlington, USA.