Dexamethasone for Prevention and Treatment of Acute Mountain Sickness

Acute mountain sickness AMS is a common malady afflicting persons ascending quickly to high altitude.Although generally not life-threatening and usually self-limiting, AMS is often incapacitating. Potentially fatal pulmonary and cerebral edema may develop in as many as five to ten percent of those with AMS. Staged ascent with adequate time for acclimatization is optimal for prevention, but is not always effective and is often impractical. Therefore, pharmacological prophylaxis has been of great interest. The current agent of choice for prevention of AMS is acetazolamide. One field study found dexamethasone also effective in preventing symptoms of AMS. The investigators gave 4mg dexamethasone every six hours starting 48 hours prior to decompression or ascent. The subjects were sedentary. We also wished to study dexamethasone as a treatment for established cases of AMS. We rapidly transported fifteen soldiers from sea level to 4400m. The study included a double-blind, placebo-controlled trial of 2mg dexamethasone every six hours starting 1 hour before flight to high altitude and subsequently a trial of 4mg dexamethasone every six hours fo the treatment of AMS. We found that the lower dose dexamethasone did not prevent AMS in active soldiers, and that the higher dose of dexamethasone was an effective treatment for those ill with AMS.