The main thing is be very supportive, resist the urge to say things like "just relax", or "Just calm down", as a person suffering from the same things as your husband for years now I find the most comforting thing is just to say "its ok, it will end soon". Panic works in a certain way, it can only get up to a certain point before the body shuts off the "fight or flight response" and you start to calm down, in other words, it cant last forever. 3 hours seems like an increadbly long time for a panic attack. I find that when the feelings last that long it is more just anxiety that never reaches the peak of panic so it goes on. You mentioned xanax, this drug is very effective, but only taken occasionally, not as an on going treatment as it is incredably addictive, both physically and mentally. You also end up needing more and more because your body quickly develops a tolerance to it. Getting off it can be a disaster if you end up addicted to it.
Maybe you should get a referal to a psychiatrist and a psychologist, they would be the most helpful people at this stage.
I agree with what Jessl writes above. Panic disorder and anxiety runs in my family and I've seen my mom and sister deal with this for years.
My sister takes Effexor for her panic attacks and it works like a charm; you'd never know she had a problem at all. Xanax is good for popping once in a while--like right before flying. It shouldn't be used to treat something like this.
Xanax would be good for an occasional pop...like the above posts say. Maybe now would be a good time to get it until the prozac kicks in. I am also on Buspar in conjuction with Paxil. Buspar is an anti-anxiety medication that works very well with anti-depressants. I truly recommend it...it has helped me greatly. It is a medication that you take every day. Please have your husband go back to the doctor for a re-evaluation. Also, let him know that there is life after and DURING anxiety and it is treatable and you can live a normal life. Ask him to join our support group here! I find that talking to people who experience the same thing is very helpful and theraputic in its own way. Its nice to know that you are not alone!!