Acetazolamide to Prevent Impending Altitude-illness in Patients With COPD

Novel Approach to Prevention of Altitude-related Illness in Patients With Chronic Obstructive Pulmonary Disease

The purpose of this randomized, placebo-controlled double-blind trial is to evaluate efficacy of acetazolamide in preventing overt altitude-related adverse health effects (ARAHE) in lowlanders with chronic obstructive pulmonary disease (COPD) developing early signs of altitude-illness during altitude travel.

This randomized placebo-controlled, double-blind, parallel-design trial will evaluate effectiveness of acetazolamide in reducing the incidence of predefined altitude-related adverse health effects in lowlanders with chronic obstructive pulmonary disease (COPD) travelling to high altitude and developping early symptoms and/or signs of impending altitude-illness. Qualifying participants will be randomized 1:1 to acetazolamide or placebo treatment during their further stay of 2 days at 3'100 m.

An interim-analysis will be performed after the first year of the study or when 38 participants are randomized, whichever comes first. Symmetric stopping boundaries at P<0.001 will be applied (Peto approach).

Inclusion criteria

• Men and women, age 35-75 y, living at low altitude (<800 m).

• COPD diagnosed according to the Global Initiative for Obstructive Lung Disease (GOLD) guidelines, forced expiratory volume in one second 40-80% predicted, pulse oximetry ≥92%, PaCO2 <6 kilopascal, breathing ambient air at 760 m.

• One of the following early signs and/or symptoms of impending altitude-illness identified by self-monitoring during ascent to or stay at 3100 m:

  • Pulse oximetry SpO2≤84%
  • Headache or nausea/vomiting or fatigue/weakness or dizziness/light-headedness of at least moderate intensity

Exclusion criteria

• COPD exacerbation, very severe COPD with hypoxemia or hypercapnia at 760 m (see above).
• Other lung disease, relevant comorbidities (such as uncontrolled cardiovascular disease, i.e., unstable arterial hypertension, coronary artery disease; previous stroke; obesity (body mass index >35 kg/m2); internal, neurologic, rheumatologic or psychiatric disease; current heavy smoking (>20 cigarettes per day).
• Renal failure and/or allergy to sulfonamides.
• Patients who do not have early signs and/or signs of impending altitude-illness by self-monitoring (as defined above) at 3'100m will not be included.