When you have to fill out the forms that ask if you have any drugs etc, make sure you write that it is for health problems. Prozac is a really common medication now, with prescription drugs the concern is whether you are bringing in a medication that isn't available in that country. It should go smoothly, you could also ask one of the customs agents standing around what you should put down on the form. And just in case I wold also put extra in your suitcase.