I just wanted to set the record straight on use of Diamox, with a brief word on current guidelines from UIAA medical advisors (plus from my own experience):
They don't recommend routine use of Diamox (aka Acetozolamide) unless 1) you are known to be susceptible to AMS or 2) such as a rescue worker, having to make a fast ascent. It is useful to treat AMS symptoms (making sure dehydration etc addressed as well) - and then may be given at the dose of one tablet twice per day (unless allergic to sulphonamide antibiotics). But at this high dose you will experience the side effects of tingling, strange taste and peeing a lot.
If you are taking Diamox to prevent AMS the first thing to note is that it isn't a substitute for a proper accimatisation program - such as (again) recommended by UIAA (climb as high as you like but don't increase your sleeping height by more than 300m (1000ft) per day above about 3000m (10,000ft approx) - and have a rest day every 3rd day).
I climbed Aconcagua at the beginning of this year and had no AMS. I summited on my 14th day into the park - so given my end point was roughly 14,000ft above my start this pretty much matched the 1000ft per day rule. I carried Diamox but didn't intend to use it other than need. As it happened although I didn't get AMS I did suffer with uncomfortable Cheyn-Stokes breathing at night above 4200m, so I took half a tablet just at night - which worked fine - and wasn't enough to provoke side effects.
If you want to know more here is a link to the article I wrote on Expedition Medicine:http://www.summitpost.org/expedition-medicine/675753
Incidentally, on the subject of Coca and high altitude my advise is DON'T!! The active ingredient is basically cocaine - which does give a lift and the illusion of extra energy etc. But at a cost - which is suppression of appetite and of the desire to drink. I saw someone using Coca on Aconcagua and he put himself and his team mates in danger when on several occasions he went down with dehydration and hypothermia (he could have died as low down as 5000m, just getting to Camp 1 - got into a terrible state, but didn't learn his lesson - and kept doing same thing all the way up - summited but then had to be half carried down by his 2 companions, who were exhausted enough by their own efforts).