Cats fighting/inapproproate elimination

Question
hi Amanda - I have 3 cats, but problems with 2 of them fighting, all fixed.  
The one male is 5, we've had him since a kitten.  We adopted a 4 y/o female 8
months ago, it said on her bio that it was "unknown" how she was with other
cats.  We did a slow introduction (her in a separate room, then seeing
eachother thru the door, etc.) until we finally let her out in the house.  They
never liked eachother, but have now become obsessive about stalking
eachother around the house, sneak attacks, fighting eachother so fur fly's,
they're leaving claws in eachothers sides, etc.  The male has also started
urinating outside of the litterbox.  Yes, we have 3 litter boxes, I keep them
clean, and he also has access to the outside, but he will not use the litterbox
(even when I make sure the girl cat has not been in it).  He urinates all over
the place...no real patten.

I am now in the process of a "reintroduction" as a means to try to get them to
stop fighting.  She is in a bedroom upstairs, and he has free roam of the
house/yard.  I also have him on amytripteline (sp?) to decrease anxiety, as he
always seem to be looking over his shoulder.   My plan was to give them a
few weeks to chill out and then start to introduce treats to eachother (they
are getting no treats now, just their regualr food) on each side of the door,
then looking at eachother through a crack in the door then finally letting her
out again.  

My question;  I just read some advice on the internet from a doctor to a
different, yet similar situation.  He suggested to put one cat in separation for
a while, then switch, so the one in separation is free and the one who was
free goes into the separation room for a while to get use to the other cats
scent, then switch again.  What are your thoughts on this, and are there any
other suggestions to make this reintroduction work??

I am sick to my stomach at the thought of having to get rid of one of them, as
I love them as my children!!  My 3rd cat is not buds with the girl either, but
for the most part they seem to avoid eachother.

THANKS!!!

Answer
Hi, Sandy!  Cats can be very tricky - since they are by nature solitary creatures, unfortunately sometimes they will never get along, but hopefully that's not the case here.  I definitely think the suggestion you got from the doctor is worth a try - I don't think it can hurt, at least.  There is also a product on the market called Feliway that I would suggest you try if you haven't already.  It comes as a diffuser so you can plug it into your wall outlets.  You may need more than one because they only cover about 800 square feet I believe.  Feliway is a compound very similar to the pheromones released by nursing mother cats.  Provided that both of your cats were nursed as babies, it can sometimes have a calming effect and help with aggressive cats and improper elimination.  It can take up to 6 weeks to see any results, but I would definitely try it if you haven't.  Sometimes Amitriptyline can also take awhile for it to completely show results, but it definitely works well for anxiety.  If these tips still don't work then the only other thing I can suggest is to segregate them in opposite ends of the house if possible.  I hope it all works out.

Amanda