Diamox (Acetazolamide) and Altitude Sickness


Altitude sickness

Anyone travelling above 3000m (9842 feet) can get altitude sickness even if they’ve not had it before on previous trips!!
High Altitude Very High Altitude Extreme Altitude
Between 2400-3658m Between 3658-5500m Between 5500-8848m
Cochabamba, Bolivia 2550m Bogota, Colombia 2645m Quito, Ecuador 2879m Cuzco, Peru 3225m La Paz, Bolivia 3658m Lhasa, Tibet 3685m Everest Base Camp 5500m Mt Everest summit 8850m Mt Kilimanjaro 5895m

 Symptoms include:

  • Headaches
  • Loss of hunger
  • Feeling sick
  • Feeling tired
  • Feeling dizziness
  • Poor sleep
  • Snoring / irregular breathing when sleeping
  • Symptoms are normally worse at night

Altitude sickness occurs more commonly when people travel to a high altitude quickly or in those with underlying conditions

Altitude sickness can be diagnosed in adults by using the a self assessment Lake Louise Symptom Score:


  • Ideally don’t fly directly to altitudes above 3000m
  • Fly lower and walk up
  • If you do fly directly do not exercise or climb for at least 24 hrs.
  • Slowly climb above 3000m
  • Acclimatise for 3 days before trekking higher
  • Try not to avoid climb more than 300-500m a day
  • Have a rest day every 3-4 days or every 600m
  • Drink plenty of water  (urine should be clear/ pale yellow and lots)
  • Eat small and often especially high calorie foods
  • Avoid alcohol and other depressants like sleeping medications/ opiate medications
  • Obviously avoid smoking


Acetazolamide (Diamox) reduces the risk of developing altitude sickness in most by helping people adjust better to lack of oxygen. It is thought that Acetazolamide causes ametabolic acidosis and therefore allows the hyperventilation to continue for longer. Acetazolamide also acts as a mild diuretic meaning more visits to urinate and thus decreasing swelling.

The dose is 250mgs a day starting a few days before climbing and 2 days when the highest altitude is reached.

As it can cause side effects like tingling toes and fingers, headaches and altered taste especially for fizzy drinks.

People with a known allergy to sulphur and or Penicillin should discuss this with their doctor.

Either Ibuprofen or Paracetamol for mild headaches are fine

Anti-sickness medication, like Promethazine, for sickness is a good idea

Low People with no prior history of altitude illness and ascending to less than 9,000 ft. (2,750 m) People taking ≥2 days to arrive at 8,200–9,800 ft. (2,500–3,000 m), with subsequent increases in sleeping elevation less than 1,600 ft. (500 m) per day, and an extra day for acclimatization every 3,300 ft. (1,000 m) Acetazolamide prophylaxis generally not indicated.
Moderate People with prior history of AMS and ascending to 8,200–9,200 ft. (2,500–2,800 m) or higher in 1 d No history of AMS and ascending to more than 9,100 ft. (2,800 m) in 1 day All people ascending more than 1,600 ft. (500 m) per day (increase in sleeping elevation) at altitudes above 9,900 ft. (3,000 m), but with an extra day for acclimatization every 3,300 ft. (1,000 m) Acetazolamide prophylaxis would be beneficial and should be considered.
High History of AMS and ascending to more than 9,200 ft. (2,800 m) in 1 day All people with a prior history of HAPE or HACE All people ascending to more than 11,400 ft. (3,500 m) in 1 day All people ascending more than 1,600 ft. (500 m) per day (increase in sleeping elevation) above 9,800 ft. (3,000 m), without extra days for acclimatization. Very rapid ascents (such as less than 7-day ascents of Mount Kilimanjaro) Acetazolamide prophylaxis strongly recommended.

© CDC Abbreviations: AMS, acute mountain sickness; HACE, high-altitude cerebral oedema; HAPE, high-altitude pulmonary oedema.

Treating altitude sickness

  • Prevention is better than cure. Take your time and ensure you’ve pre-planned acclimatisation into your schedule.
  • If you think you have altitude sickness:
    • STOP and rest where you are
    • Tell your companions
    • Complete the Lake Louise symptom score
    • DO NOT go any higher for at least a day
    • Make sure you’re drinking enough water
    • Avoid alcohol
    • DO NOT smoke
    • Avoid further exercise until you are fully recovered
    • If you don’t feel any better after 24 hours, you should go down by at least 500m
    • See a doctor if your symptoms don’t improve or get worse.


If the symptoms of altitude sickness are ignored, they can lead to life-threatening conditions affecting the brain or lungs. 

Recommendations for travel:

  • Good medical insurance that covers medical evacuationandrepatriation is strongly recommended for those travelling to area of high altitude.
  • There are risks associated with high altitude including exposure to ultraviolet (UV) radiation, cold and the risk of developing altitude sickness.
  • The higher the altitude, the higher the exposure to UV radiation.Protection against UV light should include: clothing, sunscreens, and sunglasses
  • Protection against cold should include: Clothes, gloves, hats, socks, boots, facemasks, goggles
Further information from altitude.org :