HI: I have been on Gleevec 400mg for over 13 years. I have always had to eat a full breakfast with the Gleevec to avoid nausea. It can be eggs and toast, or Oatmeal as long as its a substantial amount of food to fill the stomach for me. I am on blood pressure medication for years, and still take it everyday. I am on other medications also, but they do not interfere with my Gleevec or the way I feel. I do not take a diuretic, but the banana should help your potassium.
The best thing is not to try to dig deep to look for things that you think might be giving you trouble. Our minds can do a lot of things to us if we start questioning everything we take.
So many people read all the side effects that are printed on the slip that comes with our medications, and then you start to think your having them all. Just do the meal with your Gleevec, and you should be fine. Some people like to take the Gleevec with dinner, because they said if they have any side effects that they most likely will be sleeping before they would start.