answer:Within 30 minutes. You are taking a very high dose! 1.5 mg within a few hours? In my opinion, if I were you, I would not ever take it again. It isn’t working for you, it can be highly addictive, and it would be better if you found something more effective. The only other explanation is your pills are junk. Many years ago I took a few generic Xanax that did nothing. Now, I always get the brand. I say always, I have had two prescriptions in the last 15 years, I almost never take that drug, but it is magical when I need it. Talk to your doctor. Maybe Klonopon or Adivan would work better for you? Or, some sort of antidepressant? Do you see a psychiatrist or a GP for the meds?