Diamox (poll)

[Rob]

Looking at my Lake Louise AMS score, I see that I have moderate AMS above 8,000' with onset at 6,000'. If I were to take Diamox to avoid all symptoms every time I slept above 6,000 feet or hiked above 8,000', I'd be on Diamox most weekends because there isn't time to acclimate between Friday work-day and Saturday hike-day. If I were on Diamox most weekends, I would not mind short-term side effects (such as unusual urine odor); however, long-term effects of prolonged Diamox use (such as kidney stones) scare me.

[Rick M]

I'm glad to see in the voting that most people on this list do not use Diamox (experience, pre-acclimitization, history of AMS, physiology, ?). I really don't feel comfortable talking about this since I am not a physician with access to the most current research (and this is something that has had considerable and on going research).

In a study by the University of Zurick and others, of 705 subjects in three groupings reaching Aconcagua, the group with the with the highest percentage of reaching the summit and with the lowest (by far) incidence of Acute Mountain Sickness (AMS) was the group that had the most time for acclimatization and lowest number taking Diamox. The group with the highest rate of AMS was the group that had the highest number taking Diamox. The group with the least amount of acclimatization and a comparable number taking Diamox to the most the most successful group had half the number getting AMS.

The study concluded previous mountain exposure, pre-acclimatization and low susceptibility for AMS had the best success for reaching the summit.

Other than his personnal experience, I don't know where Norris has gotten his understanding and current recomendations from; I would be interested to read about them from an official study. My own physician sited a day or two prior to ascent and not "several days".
I think any other medical recommendations concerning prescription medicine should not be taken seriously from an individual on the net (myself included).

[Kevin]

I used to carry it but have never used it myself. A couple of friends from the east coast have, and this is what I observed:

One of them, on his first attempt up Whitney, was really hurting about 9K' (just above Lone Pine Lake) and I really thought he was toasted and would have to turn back. He took a Diamox, some water, and a bit of food. We waited about 45 minutes, and ... he said he felt fine, and was able to summit, so ... was it the Diamox? the water? the food? who knows?

The other fellow always takes Diamox, beginning a couple of days before climbing. He's rather remarkable in a way - on Whitney, at about Trail Crest, he isn't even breathing hard, and he's 66 and has done Whitney with me 3 times. Altitude doesn't seem to affect him at all, but still ... I can't convince him to NOT take the Diamox and see what happens. He feels he has too much at stake, and puts up with the extra urination. So, I can't draw any conclusions from his experience either.

As for me - altitude always seems to affect me, no matter how often I climb. In the warmer months, I try to get to at least 10K regularly, but I still get a mild headache and have raspy breathing, so I climb slowly, sip water regularly, and stop for quick rests (about 30 seconds) if my head "twinges". It works for me. I gave up hoping my body would finally adjust to altitude a long time ago, and now just try to do those things which I know will minimize its effects.

[Rob]

Diamox is not the "magic pill" I had hoped for. I used it today (4/19/2008) for the first time, and I did not notice any improvement. I'll have to reconsider my dosage, look at all other factors that might have affected my hike today, and revisit root causes of AMS.

[Norris]

I am really surprised that Diamox did not prevent AMS for you. May I ask, what dosage did you take, and when did you take it?

[Rick M]

Rick M said

A few years ago I asked my new physian for some and referenced the fact that I was on search and rescue and might go from essentually sea level to ten thousand feet in a matter of minutes if being taken up by helecopter. He declined to do so sighting its effects would take a day or two to begin working and that they wouldn't do anything for me for 24-48 hours

I asked my doctor about his data being out dated two weeks ago when I saw him and he went to the server they use and said it takes a day or two to fully kick in and my use on a search the same day I take it will not help much if at all.

Did you start taking it a day or two before you needed it?

I wonder if people that take it when the problem occurs and it soon goes away are just "acclimatizing" to the new altitude and their problems would have deminished without the Diamox. I have known, myself included, people that were experiencing AMS but went away the next day (I still believe the best recourse is to descend).

[Norris]

I went back and re-read the text on Diamox that I was thinking about when I made my earlier post about some doctors having out-of-date information. The book is "Going Higher: Oxygen, Man, and Mountains" 5th edition, page 213:

"Years ago, the recommended dosage was 250 mg three times a day, starting several days before the ascent. This dosage increased urination, especially at night, and caused some unpleasant symptoms. Now physicians generally recommend 125 mg once a day, at bedtime....If the lower dose does not prevent symptoms, one can increase the dose to 250 mg twice a day, starting on the day of ascent."

A little further on, it says:

"Because Diamox is an enzyme inhibitor and acts rapidly, you may not need to take it several days before starting your climb, as is sometimes advised".

And also:

"Unfortunately, not all doctors are familiar with the proper dose of this very useful medicine.."

Still, rereading the text, it definitely does not say that it is so fast acting that you can take it as you start up the trail, nor does it categorically state that no-one needs more than 125mg.

[Rob]

Norris, having read about side effects of long-term use of Diamox, I wanted to try a small dose (125mg) first. I took my first dose at home last Friday night, the night before the hike, second dose just before starting the hike on Saturday morning, and third dose 3 hours into hike as I ascended above 7500 feet. My hiking speed yesterday above 7500 feet was only 0.5 mph -- very slow; without Diamox I did the same leg (on Bear Canyon Trail) last December at 1.0 mph (twice the speed). A week later (12/8/2007) I ascended Vivian (without Diamox) to High Creek Camp at 1.3 mph. Without considering other factors, it would appear that Diamox slowed me down. Diamox is supposed to be a diuretic, but yesterday I did not notice any increase in urine volume. Maybe I did not take enough. Perhaps I need to increase dose to 250 mg, or perhaps I have the type of AMS that can't be managed with Diamox. I need to determine, for my body, which link is the weak link that breaks and results in AMS. I suspect that my AMS is not related to respiration; rather, I suspect that it might be related to O2/CO2 transport. In that line of thinking, late last year I was popping CoQ10 and pushing greens. Therefore, for those faster hikes last December, I might have been taking CoQ10 (I don't remember CoQ10 start/stop dates exactly. Cheapest CoQ10 I found was at Trader Joes.) I'm staring at some oxyhemoglobin graphs to try to match my symptoms with blood chemistry. My goal is to be able to conduct a fun day hike up any SoCal peak without exasperating my hiking partners. Last August on one 17-hour San G hike we returned to South Fork TH at midnight, which meant that I got home at 3 a.m. then went to work a few hours later.

[Rick M]

Hi Norris,
All kinds of info floating around out there on the internet so when I had the opportunity to ask my physician about the info he gave me earlier

sighting its effects would take a day or two to begin working and that it wouldn't do anything for me for 24-48 hours

that you said was outdated and the 2006 reference I cited from. I asked him to check again.

Seems his info might be more recent or the same as the copyright 2005 book you had been thinking about. And as you now cite from your book

you may not need to take it several days before starting your climb, as is sometimes advised".

again this sounds like a day or two (maybe less) might be the time to start taking it but, for some, maybe they might still need to take it several days before and then increase the dose for it to be effective. I am not a physician and I would recommend that anyone considering taking it consult their physician. But thanks for rechecking your source.

[Rob]

I'm going to search for more info on time-line of effects of Diamox. Diamox causes the kidneys to excrete bicarbs, lowering blood pH (simulating accumulation of blood CO2) thereby inducing increased respiration. Also, lower blood pH causes hemoglobin to bind O2 more tightly, facilitating transfer of O2 from lungs to hemoglobin, but unfortunately inhibiting the next step, transfer of O2 from hemoglobin to tissue. I'll look for more info on how long it takes Diamox to lower blood pH, and that might give me a clue about whether I should start my Diamox regimen 12, 24, or 48 hours before a hike. Reflecting on my hike last weekend, if Diamox worked against me, then perhaps my weak link is O2 transfer from blood to tissue and (contrary to common treatment for most people) I should RAISE my blood pH. I have a lot to learn. I am not a doctor, nor do I play one on TV.