So sorry to hear about Tara and her experiences at the vet. I have a Westie patient who does the exact same thing. I don't believe he's had a really bad experience at the vet (although I didn't start seeing him until he was older), but I do know he pretty much rules the house and the owner lets him get away with everything at home. So that doesn't help when we need to be in control!
I also tried alprazolam on him, with pretty much the same results you found when you gave calmex to Tara. We also have a calming dog pheromone in our exam room and I spray myself with it. My patient is fine until I try to touch him!
We finally have resorted to giving him a reversible sedative called Dexdomitor IM. He is "on to us" now, so my tech actually goes outside where he is sniffing around the grass. This last time the owner gave him a hamburger from McDonalds which distracted him enough that my tech could inject the drug in his leg. Then we wait about 10-15 min in a quiet, darkened room, and he goes to sleep. Then we can trim his nails, give him a thorough physical exam, take blood (if needed) and vaccinate him. He is then given a reversal agent and within 10 min is up and walking out the door.
It sounds extreme, but I think it makes the whole vet visit much less stressful for everyone--especially the dog and his owner! As you've found, Tara's anxiety increases with each vet visit and the oral medications are just "overrided" when she gets more anxious.
Another option to consider is to look for a vet that makes housecalls. Maybe with Tara in her own environment, with the Calmex tablets, she would be more calm and could give the vaccine. But the exam is really the important thing--the vaccines are kind of secondary.
I assume that apart from the anxiety at the vet's, she is a calm dog at home?
Hi Dr Scarlett
You are correct. She has no other behaviour issues. She is a very happy dag, she has rules and knows when she is wrong, she is easy with all other dogs and loves people. I always try to be as calm as possible but I guess her actions reflect on me and then she will pick up my anxiety increase as I feel the vet/nurse think I am at fault for the dogs behaviour, but there is really nothing we can do to ease her stress. She is all very happy to sit in the waiting room, her issue I have to agree, is the smell she picks up from them maybe? I will discuss your points with my vet and see how they would like to progress in future, as I am not prepared to go through this one more time.