Prozac side effect/ alternative

Question
I have a 7 year old cairn terrier that ruptured a disc in his back when he was 4. He had surgery that left him partially paralyzed unexpectedly.  He is now able to walk even though he has no feeling in his rear legs but while recuperating he became obsessed with his shadow( tries to bite it, bangs his head into the floor) and was prescribed Prozac.  We tried to take him off the medication once during the last 3 years but the obsessive behavior came back.  During the last 6 months he has become unpredictable with snapping/growling and most recently biting behaviors, can you suggest an alternative medication or a vet in the Seattle/ Tacoma Washington area that has expertise in this area.  I have no faith in my current vet other than for vaccinations.  Thanks for your time and any information you can give me.

Answer
SSRIs are not a drug of choice for any dog behavior, so far as I'm concerned, as the side effects can present as aggression, fear, anxiety, just as they do in humans, but the dog cannot report them to us.  It is possible the neurological damage is affecting the dog in a manner that has begun to develop brain involvement.  I suggest you find a veterinary behaviorist; such a professional is fully capable of hearing your reports, assessing the dog's behavior, and conducting such tests as are necessary to determine what's going on.  You can't just *stop* any SSRI, the animal must be weaned off it very carefully.  Tail chasing is often a symptom of neurological damage and there are many medications available to effect a "cure".  I'm not able to direct you to any individual in your area but I can point you to two sites where you can attempt to locate a veterinary behaviorist within reasonable driving distance.  If you are unable to do this, call the veterinary college in your geographical area and ask for referral or appointment with one of their specialists.  This will involve travel, perhaps several hours in each direction, but you really have no alternative:
http://www.avsabonline.org/avsabonline/
http://www.veterinarybehaviorists.org/