Varenicline
"I've tried many times to quit all without success. I have (had) a very serious addiction problem at three packs a day. I've been taking champix for about 4 weeks now and am down to less than ten cigarettes a day. But the big news is the great reduction in cravings. Cravings were always the worst part of quitting but with champix the cravings have declined to just above nil. I'm glad I started champix as I can now see a realistic end to smoking. I recommend champix to the heavily addicted like me. 

Jack."