Alternatives For Prevention of AMS?

If avalanches don’t kill you, buses may. Off to the mountains.

We all know that the best form of aclimatisation in high altitude tourism, is to let nature take its course, but few people, especially those in thriving Asian economies, can afford to spend days at 3000m and 4000m to acclimatise before they attempt to cross a 5000m pass or climb a 6000m peak. For many busy Singaporeans, Koreans and Hongkongers, 2 weeks is considered too long a vacation. How can we visit high altitude places when we have so little time? Well, most experienced Himalayan trekkers/climbers are familiar with Diamox or even dexamethsone resort to legal doping. The former, also known generically as acetazolamide, is a carbonic anhydrase inhibitor. It is also a diuretic.

Carbonic anhydrase is an enzyme that acts as a catalyst in the body’s conversion of carbonic acid to carbon dioxide and water. It also works the other way around depending on whether you have too much or too little carbon dioxide in your system. As carbonic acid is acidic, the enzyme has an important role in regulating blood pH. At high altitude, you hyperventilate to take in more oxygen. You also expel more carbon dioxide with every breath. This causes the blood pH to rise or become more alkaline. Many of the symptoms like headache and loss of appetite are caused by a rise in the pH of the blood. When carbonic anhydrase is inhibited by Diamox, significantly less carbon dioxide is lost during hyperventilation. With the body’s pH maintained, the nasty symptoms of headache and nausea can be held back.

The diuretic effect of Diamox is also important. In fact, almost any diuretic drug will have a positive effect on AMS prevention. That’s because diuresis will decrease the body’s plasma volume. The blood becomes thicker (as it would during the natural acclimatisation process) and gives the body some semblance of acclimatisation.

No drug is without its problems. Wikipedia lists some “common” adverse effects of acetazolamide include the following: paraesthesia (numbness), fatigue, drowsiness, depression, decreased libido, bitter or metallic taste, nausea, vomiting, abdominal cramps, diarrhea, black feces, polyuria, kidney stones, metabolic acidosis and electrolyte changes (hypokalemia, hyponatremia). They all sound pretty unpleasant, but the most frequently encountered side effect in my Himalayan experience is just frequent urination (polyuria). You’re not going to be worried about decreased libido when you’re climbing a mountain, would you?


Dexamethasone is a steroid. In other words, it is a drug that suppresses inflammation. It is often given to patients post-operatively to reduce morbid swelling. When AMS strikes suddenly and the condition deteriorates with ataxia and poor coordination even without further ascent, dexamethasone can be a lifesaver that helps mitigate a life-threatening episode of High Altitude Cerebral Edema (HACE). When you’re talking about saving someone’s life, you won’t be too concerned about possible side effects like rapid weight gain, sleep problems (insomnia), mood changes, acne, dry skin, thinning skin, bruising or discoloration, slow wound healing, increased sweating, dizziness, bloating, hiccups. It’s a nasty list, but the only ones I’ve observed from experience are skin discoloration, stomach bloating, loss of appetite and hiccups.

Strangely (at least to me), many people are talking about alternatives to nasty Diamox and dexamethasone. Sure, we must be cautious with made-in-India drugs, but frankly, I can’t understand why alternatives must be found unless you’re allergic to Diamox. Anyway, here are some of the more common claims made by various “social influencers”.

1. Ibuprofen
This is a very common drug that we take for headache, toothache, fever. It’s pretty mild and even children are taking it. But does it work for AMS as in the whole constellation of symptoms with root causes in blood pH? It’s not surprising how some people might “swear by it”. Since headache is usually the first symptom of AMS, taking it prophylactically will almost certainly appear to “prevent” AMS. An alternative interpretation is that it may only mask the initial symptom. Studies done on ibuprofen have been inconclusive. It also depends on how the subject (and experimenters) define AMS. Ibuprofen certainly does not have the same systemic and biochemical effects as that of a carbonic anhydrase inhibitor which deal directly with the root causes of AMS. If ibuprofen really works by virtue of its anti-inflammatory action, why not Ponstan, why not Synflex and Cataflam which are far more powerful NSAIDs? Why not Arcoxia which has a far lower incidence of allergy and gastrointestinal side effects?

2. Cocoa Leaves
It’s common knowledge that Andean porters habitually chew cocoa leaves on their trips up the mountains. Why do you think they do that? For acclimatisation purposes? Certainly not! These folks are already acclimatised to high altitude. They were born in the mountains. It’s their home. They chew the leaves just as some of our construction workers take smoke breaks. Do you think “Sherpa oxygen” will help you acclimatise?

cocoa tea

To be fair, cocoa leaves do have performance-enhancing properties, but that is not what you want if you’re thinking of preventing AMS. The faster and higher you climb, the greater your chances of getting AMS. I would leave those leaves alone if I were you.

3. Beet Juice
This one is new to me, but no, it’s not really the beet. It’s the nitrate. The study that is often quoted to support the use of beet juice to prevent AMS experimented with “nitrate-rich” beet juice against a placebo that is also beet juice except that it’s not “nitrate rich”. I’m confused here. How did one beet juice get to be nitrate-rich while the other isn’t? Could it be the nitrate and not the beet juice? Why not a nitrate rich food like celery, lettuce and spinach? Or better still, nitrate pills?

The results of the beet juice study indicate that arteries relax when the subjects were given nitrate-rich beet juice. What can we conclude? Not much, actually. Why? Because relaxed arteries may not make one less prone to altitude sickness. Food therapy is not likely to yield any significant positive results unless the food is taken in sufficient quantities over long periods of time.

4. Garlic
You may regard this as folk medicine in Nepal. Garlic soup is usually prescribed by trekking guides in teahouses where their clients are nursing a throbbing headache from AMS. The soup improves any condition that a malnourished trekker with little appetite may have and it’s difficult to tell if it’s due to the garlic. I’ve seen some “garlic soups made from fried garlic. Some are just garlic cooked in salt and water. A lowland porter of mine used to chew raw garlic. Some teahouse kitchens just add a couple of cloves (usually not more than that) into mushroom soup and call it garlic soup. I certainly have no complaints about the taste of garlicky mushroom soup, but I don’t expect too much from it in the way of AMS prevention. I seriously doubt that a clove or two of garlic can make any difference when large amounts of garlic can be eaten as food without any immediate or even near-term pharmacological effects.

Having said that, garlic contains the active ingredient allicin which benefits the cardiovascular system by slowing the hardening of arteries and lowering blood pressure (marginally). And we’re talking about a very potent garlic extract and not whole garlic here. Even in a highly concentrated form, allicin is more a wellness thing than an effective remedy for acute sickness. I’ve seen Thai villagers smear tumeric over mosquito bites instead of using effective (albeit odourous) repellent, thinking that it may prevent dengue and malaria. Garlic was probably one of the handy, homegrown household items which is all that people in the mountains could offer to unacclimatised visitors. Many guides in Nepal now carry Diamox. I don’t look forward to meeting one with a garlic garland around his neck.

5. Gingko Extract
Note that I mention gingko extract and not gingko biloba. That’s because the unprocessed gingko leaf contains toxic substances that can cause diarrhoea and headaches. Many studies have been done on gingko flavonoids from fat-burning properties to boosting memory. Again, studies vis-a-vis AMS are limited (and I don’t trust those on memory boosting at all), but it has been shown that gingko extract can render blood less viscous and more smooth-flowing. Blood flows more smoothly after its consumption, but bleeding also takes place more readily. The effective blood-thinning dose for gingko extract is pretty high. Trekkers must strike a balance between the side effects and potential benefits – if any.

Finally, it pays to note that AMS stands for Acute Mountain Sickness. We need high efficacy drugs to manage acute conditions. One tablet of Diamox or dexamethasone is almost certain to work better for your AMS than a bunch of garlic and 10 litres of beet juice.

I have touched on and will continue to touch on other aids to combating AMS on this page. Give this site a whirl and you’ll find them.