Prozac in cats ... and secondhandedly, in dogs?

Question
Ms. Connell -

This is an oddball question.  I have researched everything I can, but I just cannot find an answer.  I have a ??-year-old male cat on Prozac - 5mg per day - due to inappropriate urination issues.  It's working so far, although he's not quite himself any more.

The issue is the dog.  She gets into the litter box.  I have tried EVERYTHING I can think of to keep her from the cat poo, but I just can't.  So, here's my question: is the Prozac completely metabolized or is some of it passed (heh) in the poo?  

I ask this only because the dog has been sleeping somewhat more than usual lately, as has the cat - similar side-effects or odd coincidence?  So I got to thinking maybe by eating the poo, she was ingesting the Prozac in small quantities?

Let me know what you think.  Thanks in advance.

Answer
It is quite possible that the dog is getting some of the drug- but once it is metabolized and excreted through feces and urine I wouldn't think that it would have the same effect or even be the same drug anymore.

When you say that you have tried everything, what exactly is "everything?"
I don't really know that much about Prozac in cats so ask your vet about it. He has the drug inserts that the company sends.