Dear Shaz,
I started Glivec 400mg Feb 2008, and have been on it since then. I had the same worries that you have about side effects and could not find a satisfactory answer. I believe that I understand why now. Different side effects can appear at different times., and how serious it affect you depends somewhat in your particular circumstances. In my case the first side effect to appear was anemia, within weeks that I started taking it. Within a month or two it had dissapeared. Then I had some skin rashes appearing and dissapearing in a timescale of months, after a year these also ceased. Then I had muscle cramps, specially in my feet, which come and go. Lately, after two years of usage I have started to feel specially tired. Also, since the beginning I have experienced some swelling around my eyes which make me look very sleepy for several hours after I wake up...as I work in an astronomical observatory this has not been much of an issue as almost everybody there looks sleepy most of the time! But I guess this would be an issue if you have to be in front of customers looking your best..
As you can see in my case the side effects have been minimal. So I hope that you do as well as I did. For me the side effects have been not much of an issue, except that, if I have to give you a figure, in terms of the energy I have is probably 75% to 80% of what it used to be. I was able to give 150% during times of special need at work, now I have to plan carefully so as not to put myself in too much stress. (by the way, I am 50-something..)
Cheers,
Fernando