I checked literature on this and found that following general measures are helpful to prevent acute mountain sickness, high altitude cerebral edema (HACE) and high altitude pulmonary edema (HAPE):
- These conditions generally occur at altitudes higher than 2500 meters. Beyond that, one should not ascend more than 300-500 meters per day.
- Slow ascent, e.g. traveling by road or rail, will increase time for acclimatization and reduce risk of mountain sickness.
- Taking rest and avoiding exercise for first 2-3 days.
- High carbohydrate diet may be helpful
- One should avoid alcohol and sedatives
Following medicines have been shown to reduce the risk and are generally recommended for persons who are susceptible (e.g. those who suffered such episodes on their previous visits to high altitudes):
- Tadalafil, sildenafil
- Other drugs which have been used are bosentan and inhaled salmeterol.
Above medicines should be started one day prior and continued for 2-3 days after reaching high altitude.
If acute mountain illness does occur, following measures are useful to treat these conditions:
- Hyperbaric bag or chamber
- Drugs listed above can be used for treatment also. Dexamethasone is especially useful for high altitude cerebral edema while nifedipine is most commonly used for high altitude pulmonary edema. Nitric oxide (NO) and oxygen - nitric oxide mixture inhalation have also been shown to be helpful.
- Descent to lower altitude is most important if symptoms do not resolve quickly.
- Frusemide (or Furosemide), the classical drug for pulmonary congestion, has limited usefulness in treatment of high altitude pulmonary edema. It may cause hypovolemia (reduced blood volume) and hypotension (fall in blood pressure).