The most effective treatment for altitude sickness is descending to a lower elevation. Even dropping 1,000 feet (300 meters) can improve symptoms rapidly, especially if you minimize physical exertion on the way down. For mild cases, you can often stay at your current altitude and manage symptoms with pain relievers and rest, but the rule that overrides everything else is simple: never go higher to sleep if you have any symptoms, no matter how minor they seem.
Treating Mild Altitude Sickness in Place
Mild acute mountain sickness (AMS) typically means a headache plus some combination of nausea, fatigue, dizziness, or poor sleep. If your symptoms are manageable and not getting worse, you don’t necessarily need to descend. You can stay at your current elevation and treat symptoms directly: ibuprofen (600 mg every 8 hours) or acetaminophen (500 mg every 8 hours) for headache, and an anti-nausea medication if you’re vomiting.
The key during this period is to stop ascending. Stay at the same sleeping elevation, drink fluids, eat light meals, and avoid alcohol. Your body needs time to acclimatize, which means producing more red blood cells and adjusting your breathing patterns to compensate for lower oxygen. Most people with mild AMS feel noticeably better within 12 to 24 hours if they hold their altitude.
If supplemental oxygen is available, even a low flow of 1 to 2 liters per minute can improve a headache within about 30 minutes and resolve other symptoms over the following hours. This is rarely an option for hikers or trekkers in remote areas, but it’s worth knowing about if you’re at a ski resort or mountain lodge that stocks it.
When Descent Becomes Mandatory
If your symptoms get worse despite resting and taking pain medication, you need to go down. This is not optional. Worsening symptoms at the same altitude suggest your body is failing to acclimatize, and staying put risks progression to the two dangerous forms of altitude illness: high altitude cerebral edema (HACE), which is swelling in the brain, and high altitude pulmonary edema (HAPE), which is fluid in the lungs.
Warning signs of HACE include confusion, difficulty walking in a straight line, altered behavior, and severe lethargy. HAPE shows up as breathlessness at rest, a persistent cough (sometimes producing pink or frothy sputum), and extreme fatigue with even minimal movement. Either condition can be fatal within hours if untreated. The treatment for both is immediate descent, and the person should not descend alone.
Acetazolamide for Active Symptoms
Acetazolamide is the most commonly prescribed medication for altitude sickness. It works by changing the way your kidneys handle bicarbonate, which makes your blood slightly more acidic. This tricks your body into breathing faster and deeper, pulling in more oxygen. It’s used both for prevention and treatment, but the doses differ.
For treating active AMS symptoms, the recommended dose is 250 mg every 12 hours. For prevention, the dose is lower: 125 mg every 12 hours, started the day before ascending. In a head-to-head trial at 12,500 feet on White Mountain in California, acetazolamide outperformed ibuprofen for prevention. The ibuprofen group had a higher incidence of AMS (62% vs. 51%) and lower blood oxygen levels (85.6% vs. 88.5%). So while ibuprofen helps with the headache, it doesn’t speed up acclimatization the way acetazolamide does.
Common side effects include tingling in the fingers and toes, increased urination, and a metallic taste when drinking carbonated beverages. These are annoying but harmless. People with sulfa allergies should discuss alternatives with their doctor before a trip.
Dexamethasone for Severe Cases
Dexamethasone is a powerful steroid that reduces brain swelling. The Wilderness Medical Society considers it a more reliable treatment than acetazolamide for moderate to severe AMS and HACE. It works faster and doesn’t depend on the same kidney mechanism, making it useful when someone is already very sick.
The standard preventive dose is 4 mg every 6 hours, reserved for high-risk situations like military personnel or rescue teams being airlifted to extreme altitudes. For treatment, it serves as a bridge to get someone stable enough to descend. If used for more than 5 to 7 days, it needs to be tapered gradually rather than stopped abruptly. Dexamethasone is not a substitute for going down. It buys time.
Treating High Altitude Pulmonary Edema
HAPE requires its own treatment approach because the problem is in the lungs, not the brain. Descent and supplemental oxygen are the primary treatments. Nifedipine, a medication that relaxes blood vessels in the lungs and lowers pulmonary blood pressure, is the standard drug treatment: sustained-release 30 mg every 12 hours or 20 mg every 8 hours.
When descent is impossible or delayed and nifedipine isn’t available, medications originally developed for erectile dysfunction (tadalafil or sildenafil) can be used as alternatives. These work through a similar mechanism of relaxing pulmonary blood vessels. There’s no benefit to combining them with nifedipine. In rare cases where no medications or oxygen are available, continuous positive airway pressure (a CPAP device) can help keep the lungs open.
Portable Hyperbaric Chambers
A Gamow bag is an inflatable chamber that simulates descent by increasing air pressure around the patient. It weighs about 15 pounds and can be carried on expeditions. Inflated to its maximum pressure, it effectively lowers a person’s altitude by several thousand feet while they lie inside.
Treatment duration depends on severity. Mild AMS typically needs about 2 hours in the bag, HAPE around 4 hours, and HACE around 6 hours. This is a temporary fix, not a cure. Symptoms often return after the person exits the chamber, so it’s primarily used to stabilize someone enough to begin descending or to wait for evacuation.
How to Prevent It in the First Place
The best prevention strategy is a controlled ascent rate. Above 10,000 feet (3,000 meters), increase your sleeping elevation by no more than 1,600 feet (500 meters) per day, and build in a rest day with no altitude gain every 3 to 4 days. This gives your body the time it needs to produce more oxygen-carrying red blood cells and adjust your breathing chemistry.
If your itinerary doesn’t allow a gradual ascent, such as flying directly into a high-altitude city like Cusco or Lhasa, acetazolamide started the day before arrival is the most effective preventive medication. Staying well hydrated, avoiding alcohol for the first day or two, and keeping physical activity light during your first 24 to 48 hours at altitude all reduce your risk, though none of these replace a sensible ascent schedule.
Fitness level does not protect against altitude sickness. Highly fit people sometimes ascend faster and push harder, which actually increases their risk. Previous experience at altitude without problems is somewhat reassuring but not a guarantee, since susceptibility can vary from trip to trip.