While I sympathise wholeheartedly with your story Mark and the adverse effects Champix had on you and your fathers life I would try not to let this put everyone off taking it as an aid to quit smoking.
In complete contrast to your story I have quit smoking now for 2 months using Champix and have not had any side effects. I guess if I am honest a slight bit of nausea in the first week or so but nothing that any normal person can't handle. I have tried to quit smoking using soo many other methods its too many to write. I bet if you ask i have tried it!! Champix has really helpded. I smoked for the first two weeks I was on them and decided to quit. Once I quit it was plain sailing and apart from maybe half a dozen slight cravings in two months that has been it. The other benefit I think from Champix is that in the past I had cravings to eat lots of chocolate, sweets, crips etc... and gained lots of weight. I am not sure if its co-incIdence or not but this time I had none of the food cravings and have actually lost weight. ALhtough I have been excersing as well, so that maybe a red herring!!
They say that only 2 in 10 suffer side effects and something like 1 in 1000 suffer serious side effects. The first week you take a lower dose and gradually build it. Give it a try and if you start suffering from side effects you can't handle then stop immediately.....
At not wishing to dismiss the concerns expressed by Mark and the bad experiences (bad experiences doesn't quite quantify it) I would urge people to give it a try. I felt completely the opposite, I felt relaxed, calm and totally in control. Never before have I found it so easy to say NO to a cigarette.
P.S. I was a smoker for 16 years on 20 a day.
P.P.S. I only hope that for every sad story like Marks there are hundreds of others like me......... My thoughts are with you and your family.