Research Area: Neurological Disease Biological Activity: Varenicline is a prescription medication used to treat smoking addiction. Varenicline is a nicotinic receptor partial agonist. In this respect, it is similar to cytisine and different from the nicotinic antagonist, bupropion, and nicotine replacement therapies (NRTs) like nicotine patchesand nicotine gum. As a partial agonist, it both reduces cravings for and decreases the pleasurable effects of cigarettes and other tobacco products, and through these mechanisms it can assist some patients to quit smoking. [1]