Diamox is a brand name of a prescription drug know as acetazolamide. The medication is used for a variety of purposes including the prevention and treatment of AMS. The Food and Drug Administration (FDA) first approved acetazolamide in 1953.

The medication acidifies the blood, which causes an increase in respiration, thus accelerating acclimatization. Studies have shown that Diamox at a dose of 250 mg every eight to twelve hours before and during rapid ascent to altitude results in fewer and/or less severe symptoms of acute mountain sickness (AMS).

What Does Diamox Do?

It is actually quite fascinating how it works in the body.

Ninety percent of the blood’s carbon dioxide exists in a chemical called bicarbonate. Diamox facilitates the body to eliminate bicarbonate through urination, which makes the blood more acidic.

When the blood gets acidic, the body believes that it has more carbon dioxide in it. To gets rid of this excess carbon dioxide, the body increases ventilation. In other words, the user breathes deeper and faster, getting rid of the carbon dioxide, but also taking in more oxygen.

The manufacturer of Diamox states that in their tests:

“pulmonary function (e.g., minute ventilation, expired vital capacity, and peak flow) is greater in the acetazolamide treated group, both in subjects with AMS and asymptomatic subjects. ”

This is ultimately what helps prevent and treat altitude sickness or acute mountain sickness (AMS). Without Diamox, to adapt to higher altitude, the body counteracts the decrease in oxygen in the atmosphere by instinctively breathing faster and deeper. Diamox also increases the respiratory rate through chemistry, in effect, speeding up the acclimatization process.

Does Diamox Mask Symptoms of AMS?

Diamox does not mask the symptoms of AMS. It treats AMS.

The FDA has approved the use of Diamox to prevent and treat altitude sickness. Therefore, if you feel relief from AMS symptoms after taking Diamox, you are actually better.

The manufacturer recommends Diamox be used as a preventative measure, taken 24-28 hours prior to rapid ascent and throughout your climb (until descent). But some people use it as a treatment, taking it only when symptoms of AMS arise. The medicine should be continued until you are below the altitude where symptoms became bothersome.

Diamox is used for other purposes, like treating glaucoma, epilepsy and fluid retention. So the drug may be doing other things in the body besides increasing pulmonary function.

Should I Use Diamox to Climb Kilimanjaro?

It is a personal choice of the climber whether or not to take Diamox as a preventative measure against AMS.

One should not take any drug without considering all the consequences, whether good or bad. And that’s why Ultimate Kilimanjaro® neither recommends using Diamox nor discourages using Diamox. The decision is up to the climber.

A word of advice – if one plans to possibly use Diamox on the climb, it is important that he/she should take a dosage for a day or two while in the comfort of their home to see what the effects are.

There are some side effects to taking the drug, so one should be sure their body doesn’t have an adverse reaction before getting on the mountain with it. These side effects include: tingling hands, increased urination, hearing loss, taste loss, upset stomach, vomiting, confusion. Unfortunately, some of those side effects of taking Diamox are the same as the symptoms of AMS.

Acetazolamide comes in extended-release capsules that contain 500mg of the drug, and regular-release tablets of 125 mg, 250 mg, and 500 mg.

There are other medications and natural supplements that combat altitude sickness. You can read about these in the articles below.