A higher dose of the carbonic anhydrase inhibitor does not seem to provide any additional improvements.
Treatment with acetazolamide was found to improve symptoms of obstructive sleep apnea (OSA), according to research presented at the 2023 American Thoracic Society International Conference, held from May 19 to 24 in Washington, DC.1
Acetazolamide is a carbonic anhydrase inhibitor that stabilizes respiratory drive and has been shown to reduce loop gain—a marker indicating the stability of the respiratory control system. Although this marker is known to contribute to the pathophysiology of OSA, there is a lack of data about the efficacy and optimal dose of acetazolamide as a treatment.
Investigators are conducting an ongoing placebo-controlled, double-blind, parallel-group study to assess the efficacy and dose-dependent effect of acetazolamide in patients with OSA. The study cohort includes 49 patients with an established diagnosis of moderate to severe OSA, of which 81.6% were men aged 48 to 58.5 with a BMI between 26.8 and 30.9.
The participants were randomized between three different treatment arms: placebo, 250mg of acetazolamide and 500mg of acetazolamide. Each patient was given a single daily dose of the medication for 6 weeks. Changes in apnea-hypopnea index (AHI) and oxygen desaturation index (ODI) were assessed using anin-laboratory polysomnography. A questionnaire was used to assess side effects.
In total, 43 participants have completed the study so far. Investigators found that acetazolamide significantly reduced the AHI with a placebo-corrected improvement of 34.6% and ODI was reduced by 53.5%. There were no significant differences in AHI between doses of acetazolamide. However, more side effects—mainly paresthesia—were reported with the 500mg dose.
“These findings demonstrate that acetazolamide can improve OSA,” the authors concluded. “A higher dose yielded no additional improvement regarding AH or ODI reduction but showed more side effects.”