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July 16, 1982

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

Author Affiliations

From the Departments of Medicine (Drs Larson and Schoene) and Anesthesiology and Biophysics and Physiology (Dr Hornbein), the University of Washington School of Medicine, Seattle; and the Division of Nutritional Science (Mr Roach), Cornell University, Ithaca, NY.

JAMA. 1982;248(3):328-332. doi:10.1001/jama.1982.03330030034021

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.

(JAMA 1982;248:328-332)