<prompt> Drug used for smoking cessationVareniclineNalmefeneGabapentinAcamprosate  <response>: Varenicline Varenicline - paial agonist at alpha 3 beta 4, alpha 4 beta 2 alpha 6 beta 2 subtypes of nAChRs and agonist at alpha 7 nicotinic Acetyl Choline Receptors. Block rewarding propeies of nicotine, alcohol and drugs of abuse. Ref:- Goodman Gilman Pharmacological Basis of Therapeutics 13th Ed; Pg num:- 430 