Dexamethasone for prophylaxis and treatment of acute mountain sickness

Abstract

Acute mountain sickness (AMS) is a syndrome induced by hypobaric hypoxia in individuals who ascend rapidly to altitudes above 2500 m and may represent an early form of high altitude cerebral edema (HACE). Dexamethasone (DMS) has been advocated for treatment of HACE; several recent studies have sought to investigate its therapeutic role in AMS. Success with DMS in prophylaxis of AMS has been mixed. Five out of seven studies showed statistically significant decreases in the incidence of AMS when compared with placebo. However, all three studies investigating the treatment of AMS with DMS documented significant efficacy. The effective dose for both prophylaxis and treatment is 4 mg orally every 6–8 h at altitudes above 2050 m. In four studies, significant side effects were noted on discontinuation of DMS. The origin of rebound phenomena is uncertain, but may relate to adrenal suppression. DMS appears to be a useful adjunct to descent for the treatment of AMS. Prophylactic use should be limited to unavoidably rapid ascents, such as in rescue situations, and possibly to persons allergic or intolerant to acetazolamide.