Diamox

What is Diamox?

Diamox is a medicine used to treat pressure inside the eye (glaucoma) that can also be prescribed ‘off-label’ to treat altitude sickness. When a medicine is prescribed off-label it means that it’s used in a way that’s different to its licence. Diamox is a licensed medicine for the treatment of glaucoma, epilepsy, and fluid retention, but it’s often prescribed ‘off-label’ as an altitude sickness treatment because research has shown that it works with minimal risk or side-effects.

Off-label prescriptions are completely safe because clinicians will have read information from peer-reviewed publications that support the treatment’s use in this way. There are usually studies and clinical trials to support the use of the medication as an off-label treatment.

How does Diamox work?

The higher you go above sea level, the less oxygen there is in the air. Altitude sickness, also known as acute mountain sickness (AMS), happens when you travel to a higher altitude too quickly and don’t give your body the chance to acclimatise to the ‘thinner’ (less oxygen-rich) air. Symptoms can include breathlessness, headaches and feeling dizzy, and these are caused by insufficient oxygen entering your body. If left untreated, altitude sickness can be very serious and even fatal, but treatments like Diamox can reduce the risk.

When you take Diamox, its active ingredient causes your body to excrete bicarbonate through your urine. This reduction in bicarbonate changes the pH of your blood, making it more acidic. This increased acidity ‘tricks’ your body into thinking that there are higher levels of carbon dioxide in your blood, and acts to get rid of it through the lungs by causing you to breathe more deeply and quickly. By making your breathing quicker and deeper, this increases oxygen circulation throughout your body, lessening the symptoms of altitude sickness.^[1]

What doses of Diamox are there?

Diamox is available in a single 250mg dose. It is usually taken twice daily as soon as the symptoms begin. For prevention, it can be started one or two days before you plan to ascend to a higher altitude. Taking it before you ascend gives you the chance to adjust to any of the side effects that it may trigger, and also helps to increase the oxygen levels in your body before you experience the thinner air found at higher levels of altitude.

If you are climbing a mountain with an altitude of over 2,500m you should take Diamox before each increase in altitude over 500m.

How to take Diamox

Always take Diamox as prescribed by our clinician.

You usually start by taking it one to two days before increasing your altitude over 2,500m. It’s important to ascend slowly and to take rest days after each increase in order to take Diamox and to allow your body to adjust.

You should continue taking Diamox before each increase in altitude because your body needs to acclimatise to each new altitude that you get to.

If you have any questions about how to take Diamox you can log into your account and contact our clinician for advice.

How long does it take Diamox to work?

Studies suggest that Diamox does have some effect when taken one day before an increase in altitude, but it’s most effective when you take it two days before.^[1]

Everyone responds differently to a change in altitude, so it’s important to monitor your symptoms when you take Diamox. If you take Diamox two days before your ascent and still feel strong altitude sickness symptoms then you should return to the last altitude at which you felt well. You should then seek advice from a medical professional before attempting to ascend again.

What should I do if I make a mistake when taking Diamox?

If you take too much Diamox you should seek medical attention immediately. Go to the hospital then take your Diamox with you, so that a clinician can see what you’ve taken and how much you have used.

If you forget to take a dose of Diamox you should take it as soon as you remember. But skip the missed dose if your next one is due in two hours or less, and take your next dose as normal.

If you have any questions about how you should take Diamox or what to do if you miss a dose you can log on to your Treated account and send a message to one of clinicians to ask for advice.