If your doctor knows about your past addiction problem and still prescribed xanax, I'm assuming he/she is going to be keeping a close eye on your use of it? I'm surprised a doctor would prescribe xanax to an alcoholic.
I took prescribed xanax in the past but I had quit taking it long before I stopped drinking this last time because it was part of the problem.
It works great for anxiety, BUT - I really feel it was one of the reasons I started drinking again after 18 years sober.
It works too well, but it's got a short effectiveness window. Meaning it wears off quickly. Pretty soon I wanted to be that relaxed all the time and I started drinking. Be really careful with that stuff, some people have a very hard time coming off of it. I don't think I would take it again.
When I got sober this time seven years ago I swore off all prescriptions. Been there, not going back. I'd rather deal with the body I was given and learn to work with it with food and exercise and other psychological coping tools.