I just did a quick search and found this, hope it helps!
Altitude sickness may develop in travelers who ascend rapidly to altitudes greater than 2500 m, including those who are physically fit and in previously excellent health. Those who have experienced altitude sickness in the past are prone to future episodes. The risk increases with faster ascents, higher altitudes, and greater exertion. Symptoms may include headaches, nausea, vomiting, dizziness, malaise, insomnia, and loss of appetite. Severe cases may be complicated by fluid in the lungs (high-altitude pulmonary edema) or swelling of the brain (high-altitude cerebral edema). Most deaths are caused by high-altitude pulmonary edema.
Altitude sickness may be prevented by taking acetazolamide (Diamox) 125 or 250 mg two or three times daily starting 24 hours before ascent and continuing for 48 hours after arrival at altitude. Possible side-effects include increased urinary volume, numbness, tingling, nausea, drowsiness, myopia and temporary impotence. Acetazolamide should not be given to pregnant women or anyone with a history of sulfa allergy. For those who cannot tolerate acetazolamide, the preferred alternative is dexamethasone 4 mg taken four times daily. Unlike acetazolamide, dexamethasone must be tapered gradually upon arrival at altitude, since there is a risk that altitude sickness will occur as the dosage is reduced. Dexamethasone is a steroid, so it should not be given to diabetics or anyone for whom steroids are contraindicated.
A recent study indicates that prophylactic inhalation of 125 mcg of salmeterol (Serevent) every 12 hours reduces the risk of high-altitude pulmonary edema in those with a prior history of this disorder. See C. Sartori et al, New England Journal of Medicine (2002;346:1631-6) for further information. An alternative for those with a history of high-altitude pulmonary edema is to take oral nifedipine 10 mg every 8 hours or extended-release nifedipine every 12 hours.
Other measures to prevent altitude sickness include
Ascend gradually or by increments to higher altitudes
Avoid overexertion
Eat light meals
Avoid alcohol
The symptoms of altitude sickness develop gradually so that, with proper management, serious complications can usually be prevented. If any symptoms of altitude sickness appear, it is essential not to ascend to a higher altitude. If the symptoms become worse or if the person shows signs of cerebral or pulmonary edema, it is essential to descend to a lower altitude. A descent of 500-1000 meters is generally adequate except in cases of cerebral edema, which may require a greater descent. Travelers should not resume their ascent until all symptoms of altitude sickness have cleared. Supplemental oxygen is helpful if available. Acetazolamide, dexamethasone, and nifedipine may all be used to treat altitude sickness as well as prevent it. In most cases, acetazolamide is recommended as prevention, and dexamethasone and nifedipine are reserved for emergency treatment. Nifedipine is preferable to dexamethasone for high-altitude pulmonary edema.
Travel to high altitudes is generally not recommended for those with a history of heart disease, lung disease, or sickle cell disease. It is also not recommended for pregnant women.
