Valium worked for me but I used it as a panic stopper rather than an anxiety preventer.
I had been taking increasing doses as prescribed(3xdaily) for a few years with only marginal relief so I started experimenting.
To cut a long story short, I eventually found that if I took 1 in the morning and saved the rest until the point where anxiety built and panic started it worked better. Symptoms usually subsided quickly.
I believe this helped reduce the fear of panic because I came to believe I had instant relief at my fingertips.
This theory was proven on the rare occasions I was out and then realised I didn't have them with me.
When I told my doctor what I was doing he simply said,' If it works for you, carry on.'
They provided enough security that eventually just having them with me was enough to prevent panic. As long as I had them in my pocket I didn't need to take them.