Varenicline binds with high affinity and selectivity at α4β2 neuronal nicotinic acetylcholine receptors. The efficacy of varenicline in smoking cessation is believed to be the result of low-level agonist activity at the receptor site combined with competitive inhibition of nicotine binding. The partial agonist activity induces modest receptor stimulation that attenuates the symptoms of nicotine withdrawal. In addition, by blocking the ability of nicotine to activate α4β2 nicotinic acetylcholine receptors, varenicline inhibits the surges of dopamine release that are believed to be responsible for the reinforcement and reward associated with smoking (Foulds, 2006; Pfizer, 2006).

Foulds J. (2006). The neurobiological basis for partial agonist treatment of nicotine dependence: varenicline. Int J Clin Pract 60:571–576.
Pfizer, Inc. (2006, May). Chantix Package Insert. New York, NY.

Slide is used with permission, Rx for Change: Clinician-Assisted Tobacco Cessation. Copyright © 1999-2007 The Regents of the University of California, University of Southern California, and Western University of Health Sciences. All rights reserved.