Journal Club Rants Wilderness

Acetazolamide doses

Dosage of Acetazolamide for AMS Prophylaxis

I got a pretty heated e-mail about my advice to use a 125 mg BID (twice per day) dose of acetazolamide for AMS prevention. This dosage is in contrast to the 250 mg BID dose, generally used.

The e-mail was in good fun, but it made me want to cite the articles that I consider to be the resources on the subject. Recognizing there is controversy in this issue, I stand by my advice to start prophylaxis at the 125mg dose, BID. Here’s my source:  A great RCT that looked at the 125 vs. 375 mg BID doses, the PACE (The Prophylactic Acetazolamide Dosage Comparison for Efficacy Trial) trial.

With regard to side effects of acetazolamide; they are dose dependent. The more you take, the worse the paresthesia/numbness, the metallic taste is stronger, etc…

 Having stated my opinion, one must also be able to spot AMS that can occur even on the medication.  Stopping ascent, resting, fluids and considering stepping up to the treatment dose of acetazolamide are good things to start thinking about.

I am always up for some education, if you have any other information, let me hear about it!

I already know about several, but this is one of the better 250mg BID articles

Adventure Doc Altitude Page

Addition 11/8/2007
I found this from the BMJ Clinical Evidence, which offers a good summary of AMS prophylaxis. It mentions Acetazolamide as having dose dependent side-effects and cited the PACE trial, linked above.


  1. I took the resommended 500mg for two days before my departure to Peru last month and for one day in Lima before going to altitude in Cuzco.

    I was glad I did. My partner who was allergic to the sulfa in it did not and suffered much more than I did (one of us had to have it together) I suffered not side affects of the medicine. I then cut the does down to 250mg and continued taking it, again I was glad I did as it seemed to alleviate many of the symptoms of the altitude.

    We were at alttitude(above 13K) for about 8 days and never really acclimatized. The shortness of breath was always there albiet not as bad as to be debilitating. We did drink Coca mate the whole time and enjoyed it immensely, did it help? That I’m not really sure about and I did chew the coca leaves to, just for fun really.

    Night time was the worst for breathing though. The limbic brain kicks in and unlike during the day when one can regulate activity at night your brain tells you when to breath and at least twice during the evening we’d wake up gasping.

    I’m not too sure if any of this was age related (we’re both over 45) but none of this made us unable to engage in all of our activities.

    One seperate recommendation I might make. Include some Simethicone to your kit as at alttitude gas expands and yes that includes abdominal gas also. So while this may not affect you negativly in most activities if you and your partner don’t mind the constant feeling of needing to *break wind* or don’t care about the people around you than not to worry, although that bloated feeling in and of itself can cause at least some minor discomfort.


    ps Great blog, and feel free to check out some of mine at

  2. Good story and a great tip on the simethicone! That is an often forgotten and “not discussed” problem on altitude trips. I am also proud to say that I have a link up to your site, since day one of my blog.

    Anybody looking for some good adventure travel information and an odd group of characters should visit The site contains loads of general adventure travel related stuff, from medical missions to good restaurants around the world.

    Thanks for the comments and nice words!


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