In reply to pec:
Diamox (Acetazolamide) does not mask the symptoms of altitude sickness. It is a pretty safe drug if taken as instructed. Dexamethasone can, and is a potent steroid and it should not be used without clear instruction from a medical professional (whether direct or preemptive advice).
Diamox speeds the natural acclimation process and improves sleep at altitude, although may well not be necessary with a sensible ascent profile. It can be taken at a higher dose to help with severe AMS (and potentially in HAPE and HACE, along with nifedipine and dex respectively), but in combination with descent. It absolutely does not mask any form of mountain sickness; in fact it should be strongly considered in these circumstances, with descent being the next step if no improvement.
I suspect most Drs with independent prescribing rights on the list would have a liberal policy towards prescribing Diamox, but would want a bit more information before supplying nifedipine and dex (probably a few questions and a chat).
Cardi
Dip Mtn Med