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/ Preventative measures against altitude sickness

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Blue Straggler - on 08 Jul 2018

Feels odd posting in "Expedition & Alpine" as I see us doing only mild stuff, but here goes. 

Last year in Peru and Bolivia I spent most of my time above 3500m. Only a small bit of actual mountain walking (Salkantay trek and the slog up the "tourist" steps to Macchu Picchu). I found, after 2 days of gentle acclimatisation in Cuzco, that the standard precaution of chewing on coca leaves was incredibly effective against the typical symptoms. 

I am off to Chamonix in a few weeks' time and I recall that when I was last there in 2012, although I never got sick I also never went much above 3000m (maybe 3200m at one point) and at that altitude, I could certainly sense a thin-ness in the air. 

This year I hope to get a bit higher than 3200m. I won't be able to buy a bag of Peruvian coca leaves, so what options do I have to stave off symptoms?

Thanks
 

jon on 08 Jul 2018
In reply to Blue Straggler:

> I am off to Chamonix in a few weeks' time (… ) I won't be able to buy a bag of Peruvian coca leaves

Ha ha ha ha ha...

 

Denzil - on 08 Jul 2018
pasbury on 09 Jul 2018
In reply to Blue Straggler:

Errr usual acclimatisation protocol?

Go down some when you feel shite and take it slowly.

Misha - on 09 Jul 2018
In reply to Blue Straggler:

Well I usually go the whole hog for some of the finest Columbian - probably available in Cham. Failing that, just acclimatise over time like, you know, most people (apart from the lucky few who don’t seem to get hit by altitude - may be they’re munching coca leaves though?). 

Blue Straggler - on 09 Jul 2018
In reply to Blue Straggler:

Thanks all. 

So. 

Common sense, water and headache pills then. 

drunken monkey - on 10 Jul 2018
In reply to Blue Straggler:

And red wine

kenr - on 10 Jul 2018
In reply to Blue Straggler:

> So. 

> Common sense, water and headache pills then. 

No.

But the people who know the several better answers have gotten so bored with this topic they can't be bothered to reply to it
Yet Again.

 

 

L dryhands18 - on 10 Jul 2018
In reply to Blue Straggler:

Can you get your hands on some acetazolamide?  Not as natural but works

Aly - on 11 Jul 2018
In reply to dryhands18:

Out of interest, the number needed to treat to see benefit in AMS with acetazolomide is about 8 (for every 8 treated, 1 will benefit whereas about 4 will get side effects).

 

What is even more interesting is actually how well diamox for AMS performs compared to so many well established medical therapies. 

Blue Straggler - on 11 Jul 2018
In reply to kenr:

 

Guess what

 

I did a forum search prior to posting my OP and didn’t unearth anything that sufficiently deterred me from posting the same old question yet again. Maybe my search terms weren’t good. I do try not to repeat well-worn questions and was surprised at my failure to find answers via a forum search 

 

Thanks for your positive input 

 

 

 

 

Damo on 12 Jul 2018
In reply to Aly:

> Out of interest, the number needed to treat to see benefit in AMS with acetazolomide is about 8 (for every 8 treated, 1 will benefit whereas about 4 will get side effects).

Without a lot more info this sentence is meaningless.

Firstly, getting side effects (usually mild and harmless tingling in fingers/toes, and acidic drinks like Sprite or beer taste bad) does not mean there was no benefit as well - you can have both.

Secondly, 'treating AMS' with Diamox is never going to be the best option. It's best used prophylactically, as originally intended, not as a post-onset solution.

 

> What is even more interesting is actually how well diamox for AMS performs compared to so many well established medical therapies. 

Such as what? As above, it was not really meant to treat AMS that is already present. Taking 200-400mg of ibuprofen will relieve your headache much faster than Diamox, because it's a drug designed and suited to do so. Diamox changes the pH of your blood, which takes longer to have any beneficial effect on your body as it rises in altitude.

Damo on 12 Jul 2018
In reply to Blue Straggler:

> ... so what options do I have to stave off symptoms?

The same as you used in Cuzco - take a couple of days at or above 3000m to give your body a chance to acclimatise, and that includes sleeping up there - probably at one of the lower huts.

 

Aly - on 12 Jul 2018
In reply to Damo:

The post was written in a rush and you're right, it doesn't make as much sense as I meant, apologies for that!

I was referring to evidence from the Cochrane database of systemic reviews for commonly used classes of drugs.  The actual reference is here:

http://cochranelibrary-wiley.com/doi/10.1002/14651858.CD009761.pub2/abstract

And there is a summary on a very useful website called thennt.com here:

http://www.thennt.com/nnt/acetazolamide-prevention-acute-mountain-sickness-ams/

 

The review looked for trials where acetazomamide was used as a prophylactic intervention (rather than 'treatment, you are of course correct) to reduce symptoms of AMS in people ascending to between 4000 and 5000m.

The links have the data but the RR of 0.47, absolulte risk reduction 13% (or NNT of 7.7)

The NNH (side effects) was 2.4.

Yes, the side effects of diamox are not significant in any way, and I agree that potential benefits probably outweight the risks, but I find it fascinating that the data suggests that 7 out of every 8 people who take diamox for AMS prophylaxis won't see any benefit (outside of the placebo effect which I'm sure could be considerable given the subjective and non-specific features of AMS).

 

 

The second part of my post was more of a musing.  I intuitively think that a drug with an NNT approaching ten is "not very effective", yet I find it really interesting that many other drugs which we prescribe thinking there is a good evidence base for them (well, I do anyway) - and that most local guidelines will recommend - have considerably worse 'efficacy' with often far more significant side effects.  A few examples from the same webiste:

- Warfarin for stroke prevention in NVAF (no previous CVA) - NNT = 25

- Warfarin (vs aspirin) for stroke prevention in NVAF (no prev CVA) - NNT = 60

- Aspirin for primary prevention of MI/CVA - NNT = 1600

- PPIs for acute upper GI bleeding - NNT - no benefit

A lot of the evidence on there really surprises me, that is all.


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