Mt. Whitney Portal Store & Hostel Forums General Mt. Whitney Portal Store Message Board Diamox

Good day to everyone! I am leaving for Kilimanjaro on Monday,and I am looking forward to it very much. I know that Diamox has been discussed on this board, but a search does not produce any results. Anyhow, my doctor recommends a dose of 250 mg twice per day beginning one to two days before starting the hike. However, I have seen on the internet that 125 mg twice per day is the recommended dose. Does anyone have any experience or advice for me? I really respect the advice that I have gotten on this board in the past, and would appreciate any input you may have.

Sincerely, Docdiamond

Go with Doc Ken's advice and split the tablets in half (125mg twice a day).

I used Diamox prior to the trip I did down to Mexico (second time I've used it... the first was not a pleasant experience) and had only minor issues with altitude at about 16K on day 4.

I had started 2 days prior to the trip and on the recommedation of the guide who was driving us around, did not take any once up at altitude (he mentioned some stories about clients who had had problems that he blamed on them continuing to take the stuff up high).

I think it was a wise decision to use it in this case because we had a very aggressive schedule that had us at 14.6, 15.7 and 17.2 K on days 2, 3, and 4. I made 18.5 K without a problem on day 7.

This authority says 125 twice daily. Higher dose accomplishes little more than increasing the side effects.
High Altitude Medicine Guide

docdiamond, when you use the Search function keying on the word Diamox, be sure to adjust the time frame options to give you the period you want to look for. It's automatically set to "Newer Than 1 Week", so if you don't adjust that time frame, 1 week's history is all you'll get. I ran a search for Diamox for the past year, and came up with several good threads.

I've never used the drug, but my wife has. She definitely disliked how a full 250 mg tablet made her feel (thrumming, tingling, taste issues) and cut her dosage in half, then finally to a quarter. Even the 62.5 mg dose did the trick for her.

The caveat here is that most discussion around Diamox on this board centers on getting to 14,508 feet, and that only for a brief period. You're planning to go substantially higher so, as they say, your mileage may vary.

Have a blast on Kili, and be sure to post a TR!

Ken, I still have the original bottle with the original perscription on it (about 2 years old) and the perscribed dose is a whopping 500mg!

Thanks so much for all of the responses!

I tried 250 mg twice per day for a couple of days, so I don't think I have an allergy. So, I have now split all of my 250 mg pills into 125 mg pills, and plan to take 125 mg, probably twice per day.

Here is a follow up question for you. When do I stop taking the Diamox? Do I stop after I get to 15k or so, or do I take it until I summit (assuming I am fortunate enough to summit)? I will be on the 7 day Machame route, so we get up pretty high the first couple of days and level off, and then go on up to 19k.

Again, any info is appreciated!

Docdiamond

I was told a factor in dosage could be body weight. For me (female), a high altitude specialist MD at Stanford recommended 62.5 MG twice a day. That worked for me this summer.

A caution: I understand that the diuretic effect of diamox can cause electroyte imbalances. Twice last year, after summiting with no AMS issues at all, I ended up experiencing intermittent spaciness and dizziness after leaving altitude that continued into the next day when I was back at sea level. My doctor thinks it may be an electrolyte issue caused or exacerbated by the diuretic effect of diamox. I'll be pumping up my electrolyte intake from now on (and carrying a lab form so that I can immediately be tested if it occurs again).

Last year was the first time I used Diamox to hopefully help with Cheyne Stokes breathing that happens to me when I sleep above 10,000'. I did help a fair amount and there wasn't that horrible panic feeling upon waking up suddenly but I still awakened out of breath. The dosage I started off with was 125mg twice a day and did notice some very slight tingling in my fingers but it was no big deal. As far as the diuretic effect, there was none for me, however I do consume ALOT of water everyday whether I am on the trail or not so more frequent urination is nothing new to me. Next time I will increase the dosage to 250mg twice a day and see what improvements that brings.

P.S. The complaint that carbonated drinks tasting bad while on Diamox wasn't the case for me. The post trail cold beer was as good as ever!

You may find this helpful. Here is a simplified way of understanding how Diamox, a carbonic anhydrase inhibitor, can help at higher altitudes. This is for a basic understanding and by no means an exhaustive definition.

Physiology 101,
The body works to maintain constant blood oxygen levels. In healthy people, breathing is stimulated by the need to get rid of carbon dioxide rather than the need to breathe in oxygen. Chemical receptors identify when carbon dioxide(acidic) levels are raised and respond by making the body breathe out carbon dioxide and breathe in air through the lungs.

The drug Diamox causes the kidneys to excrete bicarbonate. By increasing the amount of bicarbonate excreted in the urine( a buffer used for ph homeostasis), the blood becomes more acidic. Acidifying the blood stimulates ventilation, which increases the amount of oxygen in the blood. This is how Diamox helped John P with Cheyne Stokes breathing while at rest.

Some sources recommend up to 1000mg daily for higher elevations so 250mg twice daily shouldn't be a problem. As with any medication, individuals react differently. I would listen to your MD or anyone who has used the medication for the purpose of AMS.

Hope this is helpful and that you are successful!
Dolbybear.

In addition to the above blood/renal effects, there is the effect of Diamox on CSF and central( brain) respiratory centers, probably more important.

The physiology comes up here as a common topic, but for now, just find the dose that you can tolerate. The benefit-to-risk curve favors a lower dose, and of course, it will NOT prevent or cure all AMS, only a slower pace or descent.

1000 mg a day would be no fun. They make 500 mg slow-release capsules for eye disease, but I don't think anyone in my medical/high altitude/wilderness community ever recommends that high dose for AMS or related illnesses. I took one once before, 1996 before I knew better, and tingled very badly all night long.

Thanks Ken. I may have a predisposition for electroyte issues (even when I am not taking diamox), as I have had some incidents on multiday backpacking trips in Yosmite and also at Burning Man, that were easily resolved by Gatorade or similar. I do drink a lot of water, so now I add electrolytes. I think her thought was that the diamox probably exacerbated the situation. Anyway, I am armed for the future....

Hope I didn't mislead anyone by breaking it down "barney style". I have found explaining physiology to my patients very beneficial while administering the medications MD's prescribe. So as the Doctor reiterated, central( brain) respiratory centers in normal people are driven by carbon dioxide levels in the blood. (Didn't I say that?)
As for the dosage, I would certainly agree with lower dosages and titrating to effect.

Sorry, not quite that simple.
The peripheral (blood) and central (CSF-cerebrospinal fluid)receptors that control respiration are different and the "blood-brain barrier" is involved, too.

Diamox effects both. The latter is more important, by stimulation of central respiratory centers, that's why it helps periodic breathing and generally facilitates the increased respiration that our bodies need at high altitude but just lag behind in doing so.

The Diamox effect peripherally to promote excretion of urinary alkali and thus acidify the blood is actually counterproductive. Years ago, ammonium chloride salts were given orally in the mistaken belief that acidifying the blood helped. Actually, it is counterproductive if taken in large quantities, and if taken on Everest would kill you by preventing the helpful left-shift in the oxyhemoglobin-dissociation curve. No risk of that on Whitney.

But again, the issue is not how does it work? but how much to take?
Covered pretty well.

oops, this may be obvious, but
Daytime CONSCIOUS,forced breathing is far more respiratory ventilation than Diamox can ever do.

It is at night that Diamox really works. That also is when you see people's UNCONSCIOUS breathing slow, resulting in periodic breathing, hypoxia, HAPE, and HACE. All far more common then. Diamox's main benefit is while you sleep.

You the man!! Thanks for keeping me "on topic". Just trying to help.

You guys are awesome! I have experienced Cheyne Stokes and I thought I would never get my breath again. No fun at all. I am glad that Diamox may help avoid this issue!

Here is another issue for you. I sometimes have irregular heartbeats (premature arterial contractions). I read somewhere that acidifying your blood and low oxygen content can stimulate PACs. Does anyone know whether using Diamox at altitude might stimulate a round of PACs?

I'm headed to Mexico in November to climb Orizaba and Itza, however wanted to try Diamox in the Sierra's this summer - so the first time I take it is not in the middle of nowhere Mexico. I got a script from my doctor who prescribed the 500mg extended release capsules twice daily...that would be 1000mg/day, any opinions on this dosage? Sounds like a lot more than you guys are taking and since its the extended release capsules I can't really break them in half or anything.

you either need a new Rx for the 250 tablets (to cut in half and take twice daily) or a new MD who is actually familiar with AMS
(most are not), or both.

The massive 1000 mg/day will pretty much guarantee side effects, especially paresthesias (tingling) bad enough to keep you awake, yet not give you any added benefit.

official recommendation says:
The dose of acetazolamide for prophylaxis is 125-250 mg twice a day starting 24 hours before ascent, and discontinuing after the second or third night at the maximum altitude (or with descent if that occurs earlier). Sustained release acetazolamide, 500 mg, is also available and may be taken once per day instead of the shorter acting form, though side effects will be more prominent with this dose.

http://www.ismmed.org/np_altitude_tutorial.htm#goldenrules

so the doctor or other provider goes to school, pays for training, certification, office expense, etc, and you want him/her to phone you in a Rx for free. Shame on you. A preacher might offer a prayer on your behalf, but he would like a donation in the offering plate.

Then again, if it's a capitated HMO, the doc gets paid whether he sees you or not. However, he is under scrutiny to save every dollar for his employer (the HMO), so he may say that the drug is not very effective and just refuse to prescribe it.(this is called rationing)

Or, if you have an established relationship (good customer) with the provider in a traditional doctor-patient setting, then they may do it for free.

Thus endeth the business class for today.

I was there for something else, and mentioned to him that I was headed to Mexico for two weeks in November. He said it would be a good idea to have HepA/HepB vaccines, Cipro 500mg (antibiotic just in case), Imodium, and Diamox. That said, I have a pretty good rapport with him - I'm pretty sure he would have phoned in both the Cipro and Diamox had I just called him up. I think whether or not you have to go see a doctor depends on your relationship.

Regarding the Diamox dosage, he's calling me in a new Rx for the 250mg tabs.

I use as little as possible, 62.5. But I also use Ginseng, Vitamin E, CoQ10 and of course the mandatory electrolytes, mine being Vitalyte. I've never had full on altitude sickness, but I don't know if I would have had any symptoms even without taking the drug and supplements.

And as far as h_lankford bringing up breathing. I train a lot on the stairmaster, treadmill, weights, hikes, etc. One workout I find important is doing the stairmaster as hard as you can do at as high of level as you can do for 1 minute to 5 minute intervals. REALLY opens up the lungs. My heartbeat (according to the stairmaster) gets up to over 170 beats a minute and I am breathing hard. My resting heartbeat has gotten back to where it was when I did marathons in my 30's, 57 beats a minute. I am now 54. So yes, breathing is very important and getting your lungs ready for working harder is important IN MY OPINION.

And Burchey....I take Snickers on every hike, whether it be an 8 miler, San Jacinto, Baldy or Whitney. It's tradition to eat one on the summit. Snickers has always worked for me :-)