Talking To The Vet About Anti-Anxiety Medication

Trucker has been home 74 days (2 months and 13 days) and has slowly been improving with some of his triggers but I feel like every time we make any sort of headway with on trigger another pops up. I know that he has what seems like an endless list of triggers to work on and that we are on a journey, this is okay. What I don't want is for it to be horrible for him along the way. I am not looking to create a roller-coaster of emotions with his life. I would really like to be able to give him a formal trainer/behaviorist to help with this process (as he is my first dog) but at this point this isn't even an option.

We have tried all the homeopathic anti-anxiety treatments per the previous vets requests but they have failed to make any real impact. His Thundershirt helps but only to take the slightest edge off in the most minor of cases. If the other homeopathic treatments are doing anything it is only this taking a very limited edge off in very minor trigger situations.

The first vet we saw we loved but she has since left the clinic we go too. The last vet that we saw swore that Trucker did not actually have anxiety or fear but that he was just adjusting to his new environment (this is a load of malarkey). We have a new vet that we truly love and that seems to understand how anxious Trucker really is, unlike the vets he has seen in the past. She is so awesome; she enters the room by opening the door as little a possible, takes off her white coat, crouches down, approaches him with her back turned, and never makes eye contact with him.

Basically this whole long explanation leads me too, how do you broach the subject of prescription anti-anxiety medication to your vet and what makes a dog a good canidate for prescription anti-anxiety medication? If a dog is started on prescription anti-anxiety medication can they be weened off it at a later date or is it a life long thing?

At first I too was wholely against putting Trucker on any sort of prescription anti-anxiety medication but I think it is time to at least explore the possibility.

Any advice would be greatly appreciated.

Sorry it is long I tried to give some background but I have been trying to track his progress here: http://www.dogforum.com/dog-training-behavior/truckers-training-jouney-253898/