Varenicline and neuronal nicotinic acetylcholine receptors: A new approach to the treatment of co-occurring alcohol and nicotine addiction?

Background and Objectives: Alcohol and nicotine dependence are serious public health problems worldwide. They are associated with substantial morbidity and mortality, as well as adverse social effects and increased healthcare costs. Although efficacious treatments are available for these disorders, additional therapeutic options are required to ensure greater treatment utilization. In this paper, we describe the empirical basis on which varenicline, a nicotinic partial agonist approved for smoking cessation, may also have utility in the treatment of alcohol addiction. Methods: We sought to identify papers examining nicotine dependence, alcohol dependence, smoking, alcohol, and varenicline for possible inclusion in the present review. We identified over 600 papers through Pubmed/Medline, PsychINFO, and Google Scholar. We found 12 papers taking into consideration the following criteria: original language English, varenicline effect on alcohol consumption. Results: Animal studies have shown that varenicline reduces alcohol consumption. Two recent studies showed that varenicline also reduces alcohol consumption in humans. Both nicotine and alcohol interact with alpha 4 beta 2 and alpha 3 beta 4 nicotinic acetylcholine (ACh) receptors located in the ventral tegmental area of the brain, inducing dopamine (DA) release at the nucleus accumbens. Varenicline binds to nicotinic ACh receptors, where it has partial agonist effects, producing a moderate and constant level of DA release both in the mesolimbic pathway and in the prefrontal cortex. Conclusions and Scientific Significance: Through these effects, varenicline may reduce alcohol craving, seeking, and consumption, in addition to promoting smoking cessation. Additional studies are needed to confirm the efficacy of varenicline in the treatment of alcohol dependence.