Hydroxyzine
"I take 100mg as a PRN for extreme anxiety/panic attacks. It works almost as well as Ativan but without the unfortunate inevitability of building up a tolerance that happens with taking benzos.The only downside is that my insurance doesn't cover it while it does cover Ativan, otherwise I would just switch over completely.

The sensation is a bit different than using benzos to stop a panic attack. Where Ativan will work very quickly in 20-30 minutes tops and smother and separate you from the sensation of panic in your chest, with hydroxyzine it takes about 45 minutes and the way the anxiety slowly petering-out sort of creeps up on you. You have to be more patient which can be awful when you're panicking but the end result is nearly identical."