I don't think this is a totally appropriate post for this forum, although I realise you are taking them legally. The simple answer is that any drug of any kind can change your brain chemistry in various ways. Any drug that produces a noticeable effect on the brain is doubly dangerous, and if you're worried about this, you should speak to your doctor, as he is the best person to advise you, not us.
I hope you understand why I'm closing this.