While one of my friend's took Diamox after he began to have symptoms of altitude sickness, and claimed it helped him feel better ... if it were me, and I was worried about minimizing/eliminating the symptoms, I would follow the standard advice of taking the stuff in advance. Harvey and/or Ken may jump in here and give you their medical opinion, but personally I think taking it AFTER the onset of symptoms is more hit or miss than building up levels in your bloodstream ahead of time. But, that's me, and YMMV - I'm just an avid hiker, not an MD.
