Dexamethasone for prevention of AMS, HACE, and HAPE and for limiting impairment of performance after rapid ascent to high altitude: a narrative review.

Acute exposure to high altitude can cause acute altitude illnesses and is associated with impaired cognitive and physical performance. The most effective preventive strategies currently recommended include environmental acclimatization (slow ascent and/or pre-acclimatization) or pharmacological support of acclimatization using acetazolamide. However, these strategies are not practical for high-altitude exposures that require rapid and unplanned ascent, high physical and mental performance, such as rescue missions or military operations. Dexamethasone and other modulators of the glucocorticoid system take effect quickly and are effective alternatives for preventing acute altitude illnesses when rapidly ascending to high altitudes. As the efficacy of dexamethasone in preventing acute mountain illnesses remains controversial, a review of existing studies on the use of dexamethasone for the prevention of acute mountain sickness was conducted, aiming to determine the best strategy. Possible mechanisms of protection against acute altitude illnesses are discussed based on the results of clinical trials. The data indicate that dexamethasone is most effective at altitudes above 4000 m at doses of 8-16 mg/d. Appropriately designed and powered trials are needed to obtain more evidence-based results on the dosage and timing of dexamethasone administration, and to provide optimized recommendations for the application of this powerful pharmacological tool.