Varenicline
"I was hesitate at first. I smoked for over 20 years. Within 10 days I didn't want to smoke.  And haven't since August 5th 2013. I did gain weight, I would be lying if I didn't tell you.  But not as much if I went cold turkey.  I know that because my girlfriend went cold turkey and I took Champix.  I gained 27 pounds....my girlfriend gained 76 pounds. To date I am working on the weight gained and proud to say a non smoker.  I am a non smoker thanks to Champix. Thank you! My children are proud of me and are happy that I quit. Without you I could not have done it. Truth be told. Thank you.  Champix saved my life. Thank you!"