Acetazolamide lowers prevalence of altitude-related adverse health effects in COPD

Key takeaways:

• Fewer patients with COPD experienced altitude-related adverse health effects at 3,100 m with acetazolamide vs. placebo.
• This therapy was safe and well tolerated.

Acetazolamide taken during stays in high-altitude areas decreases the chances for altitude-related adverse health effects among patients with COPD, according to a European Respiratory Society International Congress presentation.

“In patients testing positive by self-monitoring, taking acetazolamide can reduce the incidence of altitude-related adverse effects by 24% compared to placebo,” Konrad Bloch, MD, of the department of respiratory medicine at University Hospital of Zurich, said during the presentation.

In a randomized, placebo-controlled, double-blind, parallel trial, Bloch and colleagues analyzed 157 patients (mean age, 59 years; 72 women; FEV₁, 61% ± 12% predicted) with moderate to severe COPD who had a positive risk assessment for altitude-related adverse health effects via structured self-monitoring during a 2-day stay at 3,100 m to determine if acetazolamide therapy (375 mg/day) can stop these adverse effects from happening during further time spent at this altitude.

Structured self-monitoring involved both pulse oximetry and a symptom checklist to calculate risk and was performed four times a day, Bloch said. A patient had a positive risk for altitude-related adverse effects if they had acute mountain sickness symptoms, discomfort and/or SpO₂ less than 85%.

Compared with patients receiving placebo (n = 81), fewer patients receiving acetazolamide (n = 76) experienced an altitude-related adverse health effect, which included severe acute mountain sickness, SpO₂ less than 80% for more than 30 minutes or any condition requiring medical treatment (50% vs. 74%; HR = 0.6; 95% CI, 0.4-0.89).

These data equated to an absolute risk reduction of 24% and a number needed to treat of 3.9 patients (95% CI, 2.5-10.5) with acetazolamide to prevent one additional poor outcome.

Along with these findings, the therapy was well tolerated and did not lead to any serious adverse events in patients, according to researchers.

“A preventive strategy comprising structured self-monitoring followed by acetazolamide therapy if needed may reduce the need for preventive medication in patients with COPD at altitude,” Bloch said during the presentation.