Altitude Sickness Prevention

Acetazolamide (Diamox) is a prescription medication that speeds acclimatization by increasing your breathing rate and kidney bicarbonate excretion. It is typically taken 1-2 days before ascent and continued during the climb. Diamox is not a guarantee against altitude sickness — proper acclimatization practices remain essential even when taking the medication.

Diamox is recommended for travelers ascending above 2,500 metres (8,200 feet), especially those with a rapid ascent schedule or a history of altitude sickness. It is also advised for anyone flying directly to high-altitude cities such as Cusco, La Paz, or Lhasa. Discuss with your physician before taking Diamox if you have a sulfa allergy or kidney issues.

Common side effects include tingling in fingers, toes, and lips (very common and harmless), increased urination, altered taste of carbonated drinks, and mild nausea. We recommend starting a trial dose at home before your trip to check your tolerance and identify any adverse reactions before you are at altitude.

Yes. Gradual ascent (300-500 metres per day above 2,500 m), scheduled rest days, staying well hydrated, avoiding alcohol for the first 48 hours, and sleeping at a lower altitude than your highest point reached that day are all effective non-pharmacological strategies. Medication provides an additional layer of protection on top of these practices.

Seek immediate medical attention if you experience severe headache not responding to painkillers, confusion or loss of coordination (ataxia), persistent vomiting, shortness of breath at rest, or fluid sounds in the lungs. These symptoms suggest high-altitude cerebral edema (HACE) or high-altitude pulmonary edema (HAPE), both life-threatening conditions requiring immediate descent.

Yes — flying directly into high-altitude cities like Cusco (3,400 m) or La Paz (3,640 m) is one of the highest-risk scenarios for altitude sickness because your body has no gradual acclimatization period. Many travelers experience symptoms within hours of arrival. Starting Diamox 1–2 days before your flight significantly reduces this risk. Our travel medicine physician recommends arriving a day early in a lower-altitude city if your itinerary allows, or at minimum beginning Diamox before departure.