Island Peak with Earth's Edge 1

Johnjoe on Using Diamox

Many people when trekking at altitude take Diamox to help with altitude sickness. Using Diamox increases the amount of oxygen in your bloodstream and means you acclimatise better to altitude. That said, there can be side effects and different people will react differently to Diamox.

Luckily we’ve got Johnjoe to talk about best practice around using Diamox while you’re on a trip.

A note on using Diamox

For anyone who watched Johnjoe’s video, I hope you enjoyed it! I wanted to add some more in-depth information about Diamox and its use as a preventative for altitude sickness when climbing Kilimanjarotrekking to Everest Base Camp or on an Elbrus climb.

If you have not done so already be sure to check out our video and article on Altitude Sickness.

It’s important you consult your own doctor before taking Diamox or any other medication. Neither Johnjoe or I are medical professionals and we are only giving our own personal opinions on its usage based on our experiences.

Although the vast majority of people don’t suffer any side effect when using Diamox, they do occur and it’s important you are aware of their existence.

What is Diamox and what does it do?

Diamox (Acetazolamide) is a carbonic anhydrase inhibitor. In simple terms Diamox causes the kidneys to excrete more bicarbonate which causes the blood to become more acidic.

Acidifying the blood stimulates ventilation, which increases the amount of oxygen in the blood which reduces the chances of getting AMS.

What are the potential side effects of Diamox?

Common side effects are increased urination, numbness and tingling in your fingers and toes. A small percentage of unlucky people suffer more severe side effects such as diarrhoea, drowsiness, loss of appetite, nausea and vomiting.

While the incidences are low it can cause urinary incontinence in men, especially older men. It’s important to take Diamox for two consecutive days well before your trip, under normal dietary and exercise conditions. That way if you do suffer any side effects, you will know well in advance of your trip. If it doesn’t agree with you, it’s not the end of the world a lot a people don’t take Diamox when going to high altitude.

Should you take Diamox?

At Earth’s Edge we highly recommend you try Diamox before departure and if you don’t suffer any side effects then take it on your next trip to altitude.

It’s not going to climb the mountain for you, however, it will greatly reduce the chances of you suffering from altitude sickness. Current guidelines suggest 125mg twice per day.

If you have any questions or feedback about Diamox, email me on

All the best,


About James & Johnjoe; James McManus owns and runs Earth’s Edge. He has over 20 years’ experience and leads at least five expeditions to altitude each year. Johnjoe is his dog.

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