I've have panic attacks like the OP. They lasted pretty strongly for a year, then tapered off. Treatment: Basically, lots of benzos (Xanax) that I titrated myself off of over time. (Xanax is a much lower risk drug than some of the powerful ones a psych might prescribe (SSRIs, for example)). For years though, I couldn't do anything that put me in an altered state. Even taking Benadryl to sleep (which makes you groggy at first), would make me freak out. Even a tiny hit of pot would make me get all scared. Apart from taking Xanax on-demand, it just mostly went away...
I still keep Xanax in my pocket (I think everyone should, to be able to remain clear headed if a panic situation arises), but hardly ever need them.
When my wife was being treated for PD, she tried Xanax and hated it. She said it felt as though she was still having a panic attack but just couldn't act on it - which, for her, was even scarier.
That's the paradoxical effect. It happens, sadly, with most psychiatric medicines. No one really knows why, but a small percentage of people end up getting worse. That could have been at play with your wife. Or it could have been a nocebo (negative placebo) effect, or just the course of the attack. For example, the worst panic attacks tend to come on suddenly with a defined liminal point (not an upward creep of anxiety throughout the day) and peak 3-7 minutes afterward. If she took the Xanax at the liminal point and felt worse 5 minutes later, that's not because of the drug, but the panic attack's initial upward swing.
The truth is that benzodiazepines don't really abort a panic attack-- at least not in the short (<5 minutes) term. Nothing really can. What benzos are great for is recovering from a panic attack and preventing it from rolling into another one. If your wife felt shitty for 5 minutes, but great at T=30 minutes, then it's not the drug's fault because the drug worked.
SSRIs also have a paradoxical effect. I think SSRIs are somewhat like a less risky version of electroconvulsive therapy: they induce a change of state in the brain, and the brain's response gets it out of a depressive cycle, but it's not clear why one state change ("shock") works and another doesn't. To make it weirder, when people are on SSRIs for a while there's a tendency for the drug to stop working ("poop out"). No surprise: this sounds like tolerance. However, at this point both raising and lowering the doses can work. So it seems like any change in this state variable is what can cause the improvement, but no one really knows. (That said, never hard taper on an SSRI, and definitely don't reduce dosage without talking to a doctor.)
I'm on very low doses of Klonopin, which takes longer (about 30 minutes) to set in but I think that was a very good thing. First, there's no sudden change in psychological state. Sudden relaxation during panic could have a paradoxical effect. Second, it puts a 30-60 minute upper bound on the attack but still requires me to work at calming myself down. If it took effect immediately, I never would have had to go through the hard process of deliberately calming myself down, through which I learned a lot of skills that work on run-of-the-mill negative emotions as well as on panic. Thanks to that process, I'm probably actually above average in mental health post-panic. Panic disorder teaches in a very visceral way that most of the garden-variety worries are just not worth getting upset over.
I still keep Xanax in my pocket (I think everyone should, to be able to remain clear headed if a panic situation arises), but hardly ever need them.