Varenicline: a review of its use as an aid to smoking cessation therapy.

Varenicline is an orally administered alpha4beta2 nicotinic acetylcholine (ACh) receptor partial agonist. It has been approved by the US FDA (Chantix) and the European Commission (Champix) for use as an aid to smoking cessation therapy. Varenicline is an effective and generally well tolerated treatment for use in smokers who want to quit. In two well designed, phase III trials, 12 weeks' treatment with varenicline was associated with significantly higher continuous abstinence rates at weeks 9-12 than placebo or bupropion sustained-release (SR). In the longer term, continuous abstinence rates for weeks 9 through 52 demonstrated that the odds of remaining abstinent were 2.7 to 3.1 times higher with 12 weeks of varenicline treatment than with placebo; the significant difference between varenicline and bupropion SR was also maintained in the longer term in one trial. Moreover, varenicline appeared to attenuate the urge to smoke, negative affect withdrawal symptoms and the reinforcing effects of smoking. Among those achieving abstinence, an additional 12 weeks of varenicline therapy helped increase the likelihood of long-term abstinence. Thus, varenicline is a valuable new agent for use as an aid to smoking cessation treatment.