I mentioned this in your other thread, but here goes. I've never had a dog on Prozac, but I've seen my husband on it. A normally pretty happy person that is outgoing and active...he turned into a zombie that either bitched all the time or slept. He quit taking it after a month because he couldn't stand the side-effects anymore (and I couldn't stand him and told him I was leaving until he was straightened out) and he went to his doc who perscribed Wellbutrin 150 mg. That turned out bad, really bad, so he stopped taking that, and she gave him about half that dose. He hasn't taken it because he flipped out bad the last time and didn't want to do it again at home with me and the kids. He's going to be taking it while he's away from us to see if he can do the 2 months or so and get past the side-effects, but I don't know. Hope that's a little insight, I know it's not the same with a dog but at least DH can tell someone what's wrong or how he feels and it sounds like he and Summer felt about the same.