Does anyone have any experience with giving your dog Xanax prescribed by the vet?

My dog is an absolute terror at the vet. She will bark non stop from the moment we step into the building until the moment we step outside. From what we understand, she gets stressed and then feels like she needs to protect my husband or I from the mean scary vet. Outside of the vet she does not go crazy, she's the laziest dog ever. She is not mean and has never bitten at anyone in the office but I do not want it to ever escalate to that point so I asked the vet if there was any medication we could try. She called in a prescription for Xanax.

I get a little worried giving my pet new medicine but at this point for everyone's sanity I am willing to give it a try.

I want to know of anyone who has experience with this. I know every dog is different but was your dog groggy or lethargic? Did it not work at all?

Thanks!