[New drugs; varenicline].

Nicotine acts in the brain by releasing dopamine in the mesolimbic pathway which results in a reward effect and in dependence when used chronically. The effect of nicotine is mediated via nicotinergic acetylcholine receptors of the alpha4beta2 subtype ofwhich varenicline is a partial agonist. Varenicline can be used for quitting smoking because of two mechanisms: it acts as a partial agonist and thus reduces the symptoms of craving when quitting smoking, and it has antagonistic actions by binding the receptor instead of nicotine and therefore decreases the reward effect of nicotine. The most important side effects of varenicline are nausea, vomiting and headache. After one year, 22% of the treated group continued to abstain from smoking.