There are still a few SSRIs you have left, and some "atypicals". There's Paxil, Luvox, then there are the drugs that also work on norepinephrine like Effexor. Unless you have had a substance abuse problem in the past, I would ask for Xanax or Xanax XR (the once a day extended release) instead of the Ativan or Klonopin. Xanax, despite its detractors, has proven to be much more effective for panic attacks than the other drugs in its class. If a person had just generalized anxiety disorder or another anxiety problem, it probably wouldn't make as much of a difference, but for panic disorder, Xanax is the best. Of course, you only want to use it on an as-needed basis. Some people like BuSpar, an atypical drug, and a few like the antidepressant Wellbutrin, though it isn't prescribed as much for anxiety as the other antidepressants are. Every one of these drugs have side effects. Almost none of them are dangerous, but some of the side effects are intolerable to some people. Sexual side effects are by far the most common problem with the newer antidepressants. If all those were to fail (which is unlikely) the older antidepressants have more side effects but are still in use because they are effective, but again, those are usually a last ditch sort of thing. Have you done any therapy? Cognitive behavioral therapy can be very helpful with panic disorder, and even just talking with a therapist can be helpful. Best wishes, this stuff will get better.