Although the info I posted from wikipedia claims that it peaks in 4 hours, from my experience it it very rapid acting and helps panic attacks very quickly like within minutes, depending on how you take it. Also, in my experience, it lasts about 8 hours until your body becomes used to it, then it last a shorter amount of time. I was once on 16mg a day because I developed a tolerance. After being off it for a while I went back on and only took 4-6mg/day. It took me over 6 months to taper off. Now that I have not had the meds in a year, my doctors will not fill the medication for me. And I NEED IT!!! So you know, it's not super dangerous as directed. There is no need to go on suffering without it. Just don't take it unless you need it, and if you need it all the time... well that is better than suffering.