My Dad was switched from Aricept to Exelon recently, but not for the reasons you give.
You will find that they will likely build up the Exelon far more gradually than they did with the Aricept (a process called "titration"), this is because Exelon is known to be a higher risk for side effects like diarrhea and vomitting. You will probably find that they will increase the dosage by around 1.5mg every other week so it will take a long time to build up to the maximum 12mg/day assuming you go that high.
I would also say, from personal experience, that you may see a deterioration in the dementia symptoms, during the gap between the time the high dose of Aricept wearing off completely and the time until you move to the full dose of Exelon...effectively you'll be on a low dose of the new drug for a time.
Of course this may not happen, but we experienced a "dip" between the old and the new during the working-up period for the Exelon.
I hope that all goes well with the new medication!
Oh, you have probably been told, but it's very important to eat something with the Exelon, this helps to prevent side-effects. We had a problem, my Dad often refuses to eat, so we had to think of all sorts of things to persuade him - basically we bough a bunch of individual jam puddings as he is very sweet-toothed!
