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Should You Take Diamox to Overcome the Kilimanjaro Altitude?

When Acetazolamide (Diamox) entered the market in 1982, it was designed by drug maker Teva to treat Glaucoma.

Adventurers accidentally discovered Diamox can help overcome the high Kilimanjaro altitude by acclimating them to the effects of low oxygen pressure, which is the cause of acute mountain sickness (AMS). Unfortunately, many myths surround this “wonder drug,” and we’re here to set the record straight.

Here’s what you can really expect from taking Diamox on your Kilimanjaro climb:

Is Diamox a Wonder Drug?


In 1982 Diamox was introduced to the medical market by Teva, a pharmaceutical company. It was originally designed to treat Glaucoma, but it was later discovered that one of the effects of the drug could be used to assist high-altitude climbers in acclimatizing to the effects of low oxygen pressure, the cause of acute mountain sickness (AMS).

It is not a cure, but rather a way to lessen the impacts of rapid altitude gain. It works by chemically re-acidifying the blood. This acts as a respiratory stimulant that accelerates acclimatization. It is a diuretic that forces your kidneys to excrete bicarbonate, so expect to urinate more (and drink more water) than you normally would.

Taking Diamox on a high Mount Kilimanjaro altitude climb is not a guarantee that you will not suffer from altitude sickness, but rather lessens the risk of you getting AMS.

Just the Facts About Diamox Please

MYTH: Diamox conceals altitude symptoms.

FACT: Diamox quickens acclimatization. As acclimatization occurs, symptoms improve. Diamox does not hide anything, so if you get altitude sickness (such as when adjusting to the Mount Kilimanjaro altitude, for example) you will still have symptoms. If you feel well, you are well.

MYTH: Diamox prevents AMS during rapid ascent.

FACT: This is not a myth, but rather a partial truth. Diamox lessens AMS risks and that’s why it is recommended for climbers on fast ascents. This protection is not absolute so don’t feel assured that a rapid ascent on Diamox is without big-time risk. If you ascend so rapidly that AMS strikes, it can hit you suddenly, severely and fatally.

MYTH: Diamox prevents AMS from getting worse during ascent.

FACT: Diamox does not protect against worsening AMS with a continued ascent.

MYTH: If your stop taking Diamox during your ascent, symptoms worsen.

FACT: There is no rebound effect. When Diamox is stopped, acclimatization slows to your natural rate. If AMS is still present, it takes longer for you to improve. If AMS is not present, you still need to ascend at a managed rate. You don’t get sick simply by stopping Diamox.

The Diamox Dilemma

Like all powerful drugs, Diamox has its upsides and downsides. The side effects could include, but are not limited to, fatigue, drowsiness, tingling fingers and toes, decreased libido, vomiting and diarrhea. However, to assuage worries, consider that the World Health Organization has placed it on its list of essential medications.

Everyone tolerates the drug differently, but for maximum impact when trekking at high altitudes, such as climbing Kilimanjaro, it’s best to follow your doctor’s recommended dose- usually 125mg to 250mg one to two days before the climb and then once or twice daily throughout the ascent.

So the dilemma is this – I know I’m prone to altitude sickness, but I hate taking drugs.

Adventure travel with Tusker and its advanced medical high altitude techniques gives you as good a chance to get to the top without drugs as any company on the mountain. But there is still no guarantee. Diamox could be that extra buffer you need to help get you to the top.

Consult your doctor, do your own homework and talk to others who have used the drug. It’s your body and your climb. Prepare for the Kilimanjaro altitude properly and take it seriously.



  • Mark Zuercher
    February 17, 2017

    Made it to the top of Kili with no drugs whatsover. Took the longer Lemosho route. Did no high altitude training beforehand (took a two-week cruise instead) but have never had altitude problems before.

    • Eddie Frank
      February 17, 2017

      Maybe a cruise is all that’s required! We’ll have to test that one out. Congratulations on your summit.

  • Kent Drummond
    February 17, 2017

    I ascended Kilimanjaro in August, 2015. I live at 9,000′ here in Colorado, and have climbed all our 14,000′ peaks with no altitude problem. With the potential side effect of diarrhea, I elected to not take Diamox for the Kilimanjaro climb. I had no troubles until reaching 16,500′, and then fell behind my fellow climbers, all who were taking Diamox. As a result, I was 1/2 hour behind my mates in reaching the summit. I am a stronger climber than my companions, so I’m sure not taking Diamox was to my detriment. Should there ever be another opportunity to ascend to comprable altitude, I will definitely take Diamox.

    • Eddie Frank
      February 17, 2017

      Taking Diamox is purely a personal call, as you illustrate. There’s no guarantee of success at altitude if one uses Diamox. We see a lot of climbers opt out of the regimen, and do perfectly well. Anecdotally we’ve also seen a consistent increase in oxygen saturation among those who do take the drug, which is generally supposed to be a good thing – especially in an environment where oxygen is at a premium.

  • Nina Spencer
    February 17, 2017

    I had my wonderful, life-changing January 2011 Kili climbing experience with Tusker (about whom I STILL wax-poetic!). Took Diamox and felt great all the way to the summit. Just a teeny weeny bit of intermittent finger tingling. I write about my experience of Diamox, on pages 122 and 171, in my subsequent book entitled, A Time to Creep, A Time to Soar: Lessons learned for work and life from climbing Kilimanjaro (and also share my positive experiences of Tusker/guides, porters, fabulous food etc., on pages 6, 78, 125 and 153).
    Feel free to give me a call at 416-588-3334 if you ever want to shoot the breeze with me about my very positive experience of of climbing Kilimanjaro with terrific Tucker Trails supporting and leading the way. 🙂
    (And, lol, no one paid me to say this!) 🙂
    Nina Spencer, Keynote Speaker, TV Host, Speaker Coach, Voiceover Professional, and Bestselling Author of, Getting Passion Out of Your Profession,
    and NEWEST BOOK and KEYNOTE, A Time to Creep, A Time To Soar: Lessons Learned for Work and Life from Climbing Mt. Kilimanjaro
    Listen to Nina’s interview on Zoomer Radio AM 740 and FM 96.7 by clicking:
    Watch Nina’s Guest Appearance on TVO’s The Agenda: click second video down on home page at:
    And, if curious, feel free to view my Summit Day Video on the home page of: too! 🙂

    • Eddie Frank
      February 17, 2017

      It sounds as if your life-changing experience was a positive one. Diamox, as you know, is a personal choice. The downside is small, but the upside is fairly large. Keep on climbing!

  • Henry F.
    February 17, 2017

    I got to EBC and summited Kili with Tusker while taking diamox. Having no other high altitude climbing experience, it’s not clear to me whether it was a factor. Given the relatively mild side effects versus the potential benefits, I opted to take it, but found that the best dosage was two 125mg pills per day instead of the one 250mg pill that resulted in an annoying tingling in my neck. Prior to these climbs, I asked advice on diamox of an aquaintance who was on the infamous “into thin air” Everest climb. He had done a lot of high altitude climbs prior to Everest and dismissed the value of diamox. At the end of the day, it seems like a very personal decision.

  • Marcyn Del Clements
    February 18, 2017

    Dear Eddie and crew. I’ve used Diamox ever since I found out about it, in the mid 80’s for backpacking. But I can only take 1/4 tab. every 4-6 hours. As the side effects for me being fairly slender, are quite annoying: the tingling in my finger tips and having to pee more often, which is not an easy task at altitude, especially with a pack. But I used it on my fabulous, wonderful trek to Kibo! Not 2 days before, as advised, but that morning, and during the day as needed. It was certainly one of the factors of my summiting. Plus a little extra oxygen the night before and when we reached the crater rim. But the biggest factor in a 68 year old woman reaching the top was my caring, expert guide, Bosco! He and Michael, the “B. Bag Caboose” were my constant companions and took special care of me. I have since climbed Mt. Fuji-san which doesn’t require Diamox, just grit. But certainly, I would tell anyone wanting to summit at Kilimanjaro, to use it. That and taking the longest time to get there. The Lemosho Route. The added oxygenated blood helps a lot. You just need to adjust the dose to your body.

    • Eddie Frank
      February 18, 2017

      Marcyn: You’ve really personalized your dose and found how how to tweak it. We did an efficacy study with a Special Forces group I was training together with Dr. Michael Callahan from Harvard Medical. During the test he postulated that the Diamox should be used in the morning just before exercise, to maximize the effect of it forcing you to breathe deeper and more often; then again AFTER LUNCH (not at dinner), so as to get maximum effect when exercising. Worked much more effectively than taking it at morning and night. Added benefit is that the side effect of peeing in the night was not there, as this happened in the daytime. So that’s how we suggest climbers use the drug on our high altitude treks.

      But it’s still an individual choice, as some folks prefer (and do well) not to take it at all.

  • John garry cross
    February 18, 2017

    Made it to the summit via western breach back in early 2000s.
    Several in my party were taking it, two didn’t make the summit & one was carried down after summit ing. I was talked into taking it one day before we jumped off. I soon stopped because by the 2nd day I was struggling with diarryhea. Lots of electrolyted water to right myself, but I definitely would not take it again. Personal choice.

  • Kathy King
    February 24, 2017

    I Summited Kili in 2008. I was one of two in our Tusker group who did not take Diamox. I am allergic to sulpha based drugs. Make sure you know before you go, as having an allergic reaction to sulpha can lead to rashes, weakness and jaundice. I learned when my doc at home gave me a sulpha based antibiotic for a chest cough. And I did get altitude sickness. But Tusker took care of me and I did reach the summit. We spent that night in the crater at -10 degrees. The Tusker crew woke me up all night long to give me oxygen. We descended the next day. I had no problems.
    Kathy King

    • Derek Cowbourne
      February 26, 2017

      Kathy, I too am allergic to sulpha based antibiotics but have taken Diamox on two treks: summiting Kili with Tusker in 2011 and Kala Patthar/Everest Base Camp in 2009. Several weeks before each trek I tested small then increasing doses of Diamox and found no side effects, at home. On the treks I had no effects in Nepal but did have tingling fingers and, at higher altitudes only, mild diarrhea on Kili. My suggestion: test it and see.
      Derek C.

    • Eddie Frank
      March 5, 2017

      People with an allergy to sulfanomide need not worry any more about taking Diamox, as sulfanomides are divided into two distinct categories: antibiotics and nonantibiotics. The two groups differ in their chemical structure, use, and the rate at which adverse reactions occur. Read the scientific document here.

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