Acetazolamide in the treatment of acute mountain sickness: clinical efficacy and effect on gas exchange

Ann Intern Med. 1992 Mar 15;116(6):461-5. doi: 10.7326/0003-4819-116-6-461.


Objective: To determine the efficacy of acetazolamide in the treatment of patients with acute mountain sickness and the effect of the drug on pulmonary gas exchange in acute mountain sickness.

Design: A randomized, double-blind, placebo-controlled trial.

Setting: The Denali Medical Research Project high-altitude research station (4200 m) on Mt. McKinley, Alaska.

Participants: Twelve climbers attempting an ascent of Mt. McKinley (summit, 6150 m) who presented to the medical research station with acute mountain sickness.

Intervention: Climbers were randomly assigned to receive acetazolamide, 250 mg orally, or placebo at 0 (baseline) and 8 hours after inclusion in the study.

Main outcome measures: An assessment of acute mountain sickness using a symptom score and pulmonary gas exchange measurements was done at baseline and at 24 hours.

Main results: After 24 hours, five of six climbers treated with acetazolamide were healthy, whereas all climbers who received placebo still had acute mountain sickness (P = 0.015). Arterial blood gas specimens were obtained from three of the six acetazolamide recipients and all of the placebo recipients. The alveolar to arterial oxygen pressure difference (PAO2-PaO2 difference) decreased slightly over 24 hours in the acetazolamide group (-0.8 +/- 1.2 mm Hg) but increased in the placebo group (+3.3 +/- 2.3 mm Hg) (P = 0.024). Acetazolamide improved PaO2 over 24 hours (+2.9 +/- 0.8 mm Hg) when compared with placebo (-1.3 +/- 2.8 mm Hg) (P = 0.045).

Conclusion: In established cases of acute mountain sickness, treatment with acetazolamide relieves symptoms, improves arterial oxygenation, and prevents further impairment of pulmonary gas exchange.

Publication types

  • Clinical Trial
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Acetazolamide / therapeutic use*
  • Acute Disease
  • Adult
  • Altitude Sickness / blood
  • Altitude Sickness / drug therapy*
  • Altitude Sickness / physiopathology
  • Double-Blind Method
  • Female
  • Humans
  • Male
  • Middle Aged
  • Oxygen / analysis
  • Oxygen / blood
  • Pulmonary Alveoli / chemistry
  • Pulmonary Gas Exchange / drug effects*


  • Acetazolamide
  • Oxygen