Worked well for me going from sea level to Wheeler's summit in less than 24 hours.
Next time around I woke up early, took it on an empty stomach, had some cheap Dunkin' Donuts "breakfast" and boarded an early morning flight to Phoenix - on which I almost passed out. Figured it had to be the Diamox and haven't gone back to it since. My doc thought that was a good idea (the staying away from it part).
Your results may vary, I'm not a doctor, yaddyadya.