Hello. To make a long story short, I have taken Chantix at least 4 times in the past, and all except the 4th time it helped me tremendously to quit smoking. Sadly, I started back smoking and really want to quit... I have a brand new prescription for Chantix that I would like to begin, but I'm worried that it won't work as well or at all being I've taken it so many times... can anyone provide any information about this? Do you guys think it will work a 5th time? Could I be immune to it? Thank you.