I received this from TK in regards to Diamox:

"As regards Diamox, the obvious advantage is that when taking it the effect of the altered chemical composition of your blood on your chemo-receptors is to tell your hypothalamus to make you breathe faster, which of course compensates for the reduced volume of oxygen taken in with each breath when at altitude. The main problems are twofold, a) that this is achieved by acidifying your blood which essentially immunizes you against the therapeutic effects of the drug if you should chance to have to take it reactively after succumbing to early HAPE or HACE, which is still a possibility despite taking it prescriptively, and b) that the drug is strongly diuretic, and climbers can struggle to maintain an adequate level of hydration at altitude where so much moisture is lost to the dry air (because exhaled air is moisture-laden and inspired air is not, and respiratory rate is obviously very high when exerting oneself at elevation), so moisture loss is very heavy just through breathing – let alone increased urination aggravated by cold and Diamox.

If you do not take the drug and you begin to succumb to severe AMS, our guides would give you Diamox and you could improve. If you are already taking Diamox and you start to succumb, we will need to move straight onto quite a strong oral steroid, Dexamethasone.

In our experience, while there are perhaps fewer headaches around 4,000m amongst those who take the drug, we have never really been able to identify any correlation between its use and summit success, and amongst those who do take the drug and yet subsequently succumb to severe AMS we find fewer are able to be restored to health while on the mountain and more need to descend prior to assaulting.

Sorry it’s not a clear cut issue."

Any other opinions?

Thank you.

I have never taken Diamox but have administered it to a member of my party so I cannot speak first hand about its effects on me. I did not see excessive urination in my teamate but she did describe tingling of her extremities. Her headache and nausea greatly subsided and her appetite returned.

That said, in a situation where a climber has developed HAPE or HACE, my inclination would be to get them down, not to attempt to restore them to health on the mountain. Proper accilimitization is key to the success of any atempt on a high peak.

Another little known risk of taking Diamox is that 1-2% of people taking it get kidney stones. I should know. It happened to me but fortunately not until after I was off the mountain. No doubt, dehydration plays an important role in this. Drinking sufficiently helps to prevent kidney stones. I won't take Diamox again prophylactically after that experience.

Source.