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Am J Med. 2018 Feb;131(2):200.e9-200.e16. doi: 10.1016/j.amjmed.2017.05.034. Epub 2017 Jun 28.

Budesonide Versus Acetazolamide for Prevention of Acute Mountain Sickness.

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Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, Calif. Electronic address:
Department of Emergency Medicine, Stanford University School of Medicine, Palo Alto, Calif.
Department of Computational Science, University of Colorado, Boulder.
Emergency Medicine Residency L.A. County, University of Southern California, Los Angeles.
Stanford-Kaiser Emergency Medicine Residency, Palo Alto, Calif.
Emeregency Medicine Residency, University of Chicago School of Medicine, Ill.
Division of Pulmonary & Critical Care Medicine, Stanford University School of Medicine, Palo Alto, Calif.
Department of Emergency Medicine, Institute for Altitude Medicine, University of Colorado, Boulder.



Inhaled budesonide has been suggested as a novel prevention for acute mountain sickness. However, efficacy has not been compared with the standard acute mountain sickness prevention medication acetazolamide.


This double-blind, randomized, placebo-controlled trial compared inhaled budesonide versus oral acetazolamide versus placebo, starting the morning of ascent from 1240 m (4100 ft) to 3810 m (12,570 ft) over 4 hours. The primary outcome was acute mountain sickness incidence (headache and Lake Louise Questionnaire ≥3 and another symptom).


A total of 103 participants were enrolled and completed the study; 33 (32%) received budesonide, 35 (34%) acetazolamide, and 35 (34%) placebo. Demographics were not different between the groups (P > .09). Acute mountain sickness prevalence was 73%, with severe acute mountain sickness of 47%. Fewer participants in the acetazolamide group (n = 15, 43%) developed acute mountain sickness compared with both budesonide (n = 24, 73%) (odds ratio [OR] 3.5, 95% confidence interval [CI] 1.3-10.1) and placebo (n = 22, 63%) (OR 0.5, 95% CI 0.2-1.2). Severe acute mountain sickness was reduced with acetazolamide (n = 11, 31%) compared with both budesonide (n = 18, 55%) (OR 2.6, 95% CI 1-7.2) and placebo (n = 19, 54%) (OR 0.4, 95% CI 0.1-1), with a number needed to treat of 4.


Budesonide was ineffective for the prevention of acute mountain sickness, and acetazolamide was preventive of severe acute mountain sickness taken just before rapid ascent.


Acetazolamide; Acute mountain sickness; Budesonide; High altitude; Prevention

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