I've posted on here before, but here's the awful situation as briefly as possible:
Eight months ago my wife and I adopted a rescued JRT/Beagle mix. We think he is about 4 years old. Our understanding is that he came out of an abusive situation.
He is very sweet and loving and extremely attached to us, but he has now biten 8 separate people (my wife and I several times each) badly and in very different situations. It's a true Jeckle and Hyde scenario. When he bites he is VICIOUS and in a completely different state. Afterwards he always looks extremely remorsefull. Here's the basic breakdown of the biting behaviours.
* Fear based biting: Usually he'll get startled by being touched when he's not expecting it. We've learned to be careful about this and always "let him know" when we're coming. We're also getting him used to being touched on his rump (where I presume he was repeatedly hit). We've made some progress in this area, but I have been bitten when attempting to move him when he's curled up on a couch or bed (and yes, I know he shouldn't really be in the bed).
*Extreme Resource Guarding: He gets so possesive of "prizes" that he picks up on his walks that he has growled and lurched repeatedly at us, breaking skin several times.
*Outright Attack: This is the one that concerns me most. My parents were taking care of him this weekend (they have a King Charles Spaniel our dog has always gotten along with). Over the course of 5 days he became increasingly protective of the house and displayed more and more jealousy and dominance. My Aunt pulled up to their house on Saturday, and as soon as my mother opened the door a crack, the dog ran for my aunt and just started attacking her. She was not seriously hurt, but when my mother attempted to intervene, he attacked her, biting her hand and arm badly several times. He had never attacked someone like this.
Our concern here is the unpredictability of the dog, and the fact that this "attack mode" is like a switch. It happens instantaniously, and when this switch is triggered the dog is very dangerous. We have considered anxiety medications (doggie Prozac etc.) but I have a feeling this trigger is not going to be affected by simply using drugs to make him calmer overall. Additionally, it doesn't seem to be a trainable behavior because it doesn't seem like something he's even aware of, and we certainly don't want to trigger this behavior anyway (especially if he's damaged from years of abuse).
We love him and we are heartbroken to give him up. He is a great dog 99% of the time, but that 1% is VERY scary and I'm concerned that the next time it will be a stranger or child getting hurt. I guess I'm just looking for any thoughts regarding anxiety disorders/medications or more specifically, if it sounds as though that's a viable solution. If giving him up is the safest thing, that's what we'll do, but I need to know that we've done everything we can do to try to "fix" this. Any thoughts are very much appreciated.