Varenicline
"I'm on day 7 of chantix and I have to say, I feel great!  Energetic, positive. I'm very sensitive to medication and was a little weary, still am. I make sure to take on full stomach and a full glass of water. Not a single side effect. After 3 days, I've noticed that I'd go several hrs and not smoke, which never happens with me. I smoke at least a pack a day. I find that I have to remind myself to smoke or when I see someone smoking, I think, oh yea, have a cigarette. The cravings are all but gone. It's simply habit now. They even taste bad. I've decided to make my quit day after the dosage doubles. Just to be sure. I don't see it being a problem. Highly recommend. Also, the website has a 'co-pay' system to help with the cost."