Acute Mountain Sickness and Acetazolamide: Clinical Efficacy and Effect on Ventilation

Eric B. Larson, Robert C. Roach, Robert Blair Schoene, Thomas F. Hornbein

Research output: Contribution to journalArticlepeer-review

122 Scopus citations


Sixty-four climbers participated in a randomized clinical trial of acetazolamide prophylaxis for acute mountain sickness (AMS) during rapid, active ascent of Mt Rainier. Twenty-nine (93.6%) of 31 climbers receiving acetazolamide and 25 (75.8%) of 33 receiving placebo attained the summit. Time spent ascending from sea level to the summit (4,394 m) averaged 33.5 hours (range, 23 to 48 hours). On the summit AMS was less common in climbers receiving acetazolamide, and they experienced less headache, nausea, drowsiness, shortness of breath, and dizziness and a greater sense of satisfaction and psychological well-being. Minute ventilation on the summit was significantly greater in subjects taking acetazolamide (24.9 ±2.0 L/min compared with 16.9 ±3.8 L/min). Expired vital capacity was also greater on the summit in the acetazolamide group (6.9±0.4 L compared with 5.8 ±0.4 L). We conclude that acetazolamide is effective in the prophylaxis of AMS for climbers attempting rapid, active ascent. Increased ventilation at altitude, producing an increased alveolar oxygen tension, may be related to the observed amelioration of symptoms.

Original languageEnglish (US)
Pages (from-to)328-332
Number of pages5
JournalJAMA: The Journal of the American Medical Association
Issue number3
StatePublished - Jul 16 1982
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Medicine(all)

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