Recruiting
Phase 2

Acetazolamide

Sponsor:

UCLA

Code:

NCT05804084

Conditions

Obstructive Sleep Apnea

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Interventions

Acetazolamide

Placebo

Study Details

Brief summary:

Obstructive sleep apnea (OSA) is a severe type of snoring causing people to choke in their sleep. It affects millions of Americans, causing many health problems. For example, patients with OSA often feel very sleepy and are at risk of falling asleep while driving. OSA also causes elevated blood pressure, memory problems and can severely affect quality of life. Patients with OSA are often treated with a face-mask that helps them breath at night but can be difficult to tolerate. In fact, about half the patients eventually stop using this mask. Because there are few other treatments (and no drug therapy), many OSA patients are still untreated.

Acetazolamide (a mild diuretic drug) has been used for over 50 years to treat many different conditions and is well tolerated. Recent data suggest, that acetazolamide may help OSA patients to not choke in their sleep and lower their blood pressure. Further, its low cost (66¢/day) and once-daily dosing may be attractive for OSA patients unable or unwilling to wear a mask each night. But previous studies had many limitations such as studying acetazolamide for only a few days and not capturing important outcomes. The goal of this study is to test if acetazolamide can improve sleep apnea, neurocognitive function and quality of life in adults with OSA, and to assess how it does that. Thus, the investigators will treat 60 OSA patients with acetazolamide or placebo for 4 weeks each. The order in which participants receive the drug or placebo will be randomized. At the end of each 4 week period the investigators will assess OSA severity, neurocognitive function and quality of life. Thus, this study will help assess acetazolamide's potential value for OSA treatment, and may also help to identify patients who are most likely to respond to acetazolamide.

Ultimately, this work promises a drug therapy option for millions of OSA patients who are unable to tolerate current treatments

Conditions

Obstructive Sleep Apnea

Study ID

NCT05804084

Start date

May 16, 2023

Status verified date

May, 2026

Completion date

Oct 31, 2026

Anticipated

Primary completion date

Oct 31, 2026

Anticipated

Eligibility Criteria

Eligibility Criteria

Sex: All

Age: 18+

Healthy Volunteers: Not accepted

Inclusion Criteria:

  • Age ≥18 years
  • Body mass index ≤ 35 kg/m2
  • Untreated moderate/severe OSA (AHI ≥15/h)

Exclusion Criteria:

  • Substantial sleep hypoxemia (SpO2<80% for >10% of the monitoring time during the home sleep test, or for >25% of the total sleep time during any of the in-laboratory studies)
  • Abnormally low blood counts/electrolytes or renal function at baseline
  • Use of OSA therapy during the past 1 month, or plans to urgently resume/(re)start clinical OSA therapy within 3 months
  • Significant, uncontrolled cardiac, pulmonary, endocrine, renal, hepatic, neurocognitive, psychiatric, or urologic (e.g., kidney stones) disorder
  • Other major sleep disorder (e.g., narcolepsy)
  • Urgent need to initiate effective OSA therapy (i.e., Epworth sleepiness score >18, commercial driver, prior sleep-related car accident, or based on MD judgment)
  • Severe allergy to sulfa-drugs or taking another carbonic-anhydrase inhibitor (e.g., topiramate)
  • Pregnancy/breastfeeding (current/planned)
  • Prisoners
  • Illicit substance abuse or >2 standard drinks of alcohol/day
  • Medications that may affect OSA or ventilatory control (e.g., opiates, sedatives)
  • Thiazide/loop diuretic (risk of hypokalemia)
  • Inability to give consent or follow procedures
  • Safety concern based on MD judgment

Study Design

Enrollment

60 participants

Anticipated

Allocation

Randomized

Intervention Model

Crossover

Primary purpose

Treatment

Interventions and Outcome Measures

Arms

experimental: Acetazolamide, then Placebo

Subjects will start with a 4-week ACETAZOLAMIDE regimen

Day 1-27: Acetazolamide 500mg at bedtime at home Day 28: Acetazolamide 500mg at bedtime in the sleep laboratory

After a wash-out period, subjects will then cross-over to a 4-week PLACEBO regimen:

Day 1-27: Placebo (matching Acetazolamide 500mg) at bedtime at home Day 28: Placebo (matching Acetazolamide 500mg) at bedtime in the sleep laboratory

experimental: Placebo, then Acetazolamide

Subjects will start with a 4-week PLACEBO regimen

Day 1-27: Placebo (matching Acetazolamide 500mg) at bedtime at home Day 28: Placebo (matching Acetazolamide 500mg) at bedtime in the sleep laboratory

After a wash-out period, subjects will then cross-over to a 4-week ACETAZOLAMIDE regimen:

Day 1-27: Acetazolamide 500mg at bedtime at home Day 28: Acetazolamide 500mg at bedtime in the sleep laboratory

Interventions

Acetazolamide

Acetazolamide tablet (encapsulated)

Placebo

Sugar capsule manufactured to match encapsulated Acetazolamide

Primary outcome measure

  • Apnea Hypopnea Index (AHI) [ Time Frame: 4 weeks ]

Central Contacts and Locations

Central contacts

Pamela DeYoung, RPSGT

858 246 2183sleepresearch@health.ucsd.edu

Locations

UC San Diego; Altman Clinical and Translational Research Institute Building

Recruiting

La Jolla, California, United States, 92121

More Information

Sponsor

University of California, San Diego

Last update posted

May 8, 2026

Last verified

May, 2026

Keywords

  • Obstructive Sleep Apnea
  • OSA
  • Acetazolamide
  • Precision medicine

Trial information was received from ClinicalTrials.gov and was last updated on 2026-09-26. This information was provided to ClinicalTrials.gov by University of California, San Diego on 2026-05-08. Recruitment status is synced daily from ClinicalTrials.gov and may not reflect the sponsor's current status. Confirm during your call.