Obstructive Sleep ApneaPhase 2PANACEANCT05804084
Patient-centered and Neurocognitive Outcomes With Acetazolamide for Sleep Apnea
A Phase 2 study testing Acetazolamide in people with Obstructive Sleep Apnea, run by University of California, San Diego at 1 site in United States.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Obstructive Sleep Apnea
- What is being tested?
- Acetazolamide
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 60 participants
- Where
- 1 siteUnited States
- Study dates
- 16 May 2023to 31 Oct 2026
- Phase
- Phase 2
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- Age ≥18 years
- Body mass index ≤ 35 kg/m2
- Untreated moderate/severe OSA (AHI ≥15/h)
Who cannot join
- 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)
Show all 14Show fewer
- 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
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site, 1 recruiting
- Recruiting
UC San Diego; Altman Clinical and Translational Research Institute Building
La Jolla, California, 92121
Pamela DeYoung, RPSGT
About this study
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
Read the detailed description
The goal of this randomized, controlled, double-blind clinical trial is to compare the medication acetazolamide 500mg/day against placebo in adults who have at least moderate severe obstructive sleep apnea. The main questions this trial aims to answer are:
Is acetazolamide for 4 weeks more effective than placebo for treating obstructive sleep apnea? Is acetazolamide for 4 weeks more effective than placebo for improving neurocognitive function and quality of life? What are potential predictors and mechanisms of improvements with acetazolamide in sleep apnea, neurocognitive function and quality of life?
Participants will undergo the following activities:
- Eligibility screening (online or via phone; ~10min)
- Subjects who screen positive: in-person eligibility assessment (~1h) including a history, exam, blood testing, plus an overnight home sleep test
- Participants who are eligible: will come to the research lab (~15min) and be provided with a 4-week supply of the first study drug (i.e. acetazolamide or placebo) to be taken each night at home. Neither the researchers, nor the participants will know whether participants received acetazolamide or placebo. During this 4-week period, participants will wear a watch-sized activity tracker to measure their sleep amount and researchers will check in on participants weekly; at the end of the 4-week period participants are asked to come in for an overnight visit (~12h) which includes the following activities: general exam, questionnaires (e.g. quality of life), blood test, neurocognitive function tests, and an overnight sleep study to assess the severity of sleep apnea
Researchers will compare the effects of acetazolamide on sleep apnea severity, neurocognitive function and quality of life with the effects of placebo to see if acetazolamide may be an effective treatment for select patients with sleep apnea.
- Conditions
- Obstructive Sleep Apnea
- Being tested
- Acetazolamide, Placebo
- Keywords
- Obstructive Sleep Apnea, OSA, Acetazolamide, Precision medicine
- Medical subject headings
- Sleep Apnea, Obstructive
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
AcetazolamideDrug
Also called Diamox
Acetazolamide tablet (encapsulated)
PlaceboDrug
Sugar capsule manufactured to match encapsulated Acetazolamide
| Study group | Role | What they receive |
|---|---|---|
| Acetazolamide, then Placebo | Experimental | 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 Receives: Drug: Acetazolamide; Drug: Placebo |
| Placebo, then Acetazolamide | Experimental | 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 Receives: Drug: Acetazolamide; Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Apnea Hypopnea Index (AHI)
The AHI is a measure of sleep apnea severity and is defined as the number of apneas (no breathing for 10+ seconds) and hypopneas (reduced breathing for 10+ seconds associated with a >=3% desaturation or cortical arousal) per hour of sleep.
Alternative definitions of the AHI will be explored as well (e.g. hypopneas based on 4% desaturations, or position/sleep-stage specific AHIs).
Measured: 4 weeks
Secondary outcomes (11)
Hypoxic Burden (percent*minute/hour)
Respiratory event-associated area under the desaturation curve from pre-event baseline (continuous outcome with units being "percent*minutes/hour")
Measured: 4 weeks
Overnight Memory Improvement (change in percentage points)
Based on Verbal Paired-Associates task
Measured: 4 weeks
Cognitive function composite score
Total composite score from the National Institutes of Health (NIH) Toolbox based on 7 cognitive domains which will also be explored separately and via subscales (i.e., (Fluid and Crystaliized Cognition Composite Scores). These scores are based on a T-Score metric, with a normative mean of 50 and an SD of 10. Higher scores indicate better cognitive function.
Measured: 4 weeks
Response Speed
10-minute Psychomotor vigilance task (PVT)
Measured: 4 weeks
Patient-Reported Outcomes Measurement Information System (PROMIS) Sleep Disturbance (SDA) instrument
Based on response pattern scoring, the PROMIS 8-item SDA score will be converted into a T-score with a mean of 50 (reflecting the average for the United States general population) and a standard deviation of 10. Higher t-scores reflect greater sleep disturbance.
Measured: 4 weeks
Patient-Reported Outcomes Measurement Information System (PROMIS) Sleep-Related Impairment (SRI) instrument
Based on response pattern scoring, the PROMIS 8-item SRI score will be converted into a T-score with a mean of 50 (reflecting the average for the United States general population) and a standard deviation of 10. Higher t-scores reflect greater sleep-related impairment.
Measured: 4 weeks
Epworth Sleepiness Scale (ESS) Score
The ESS is an 8-item instrument assessing the likelihood of dozing off in 8 different situations with points for each item ranging from 0 to 3 (0 = would never doze off; 3 = high chance of dozing off). The points for each item are summed up, thus the total score ranges from 0 to 24, with higher ESS scores indicating greater sleepiness.
Measured: 4 weeks
Functional Outcomes of Sleep Questionnaire 10 (FOSQ-10)
The FOSQ-10 is a 10-item instrument assessing sleep-related quality of life across 5 domains (general productivity, activity level, vigilance, social outcomes, intimacy and sexual relationships). Each item is scored on a scale ranging from 1 to 4 (a higher number indicates a better functional status for that item).
The mean scores of the 5 subscales are averaged and then multiplied by 5 to calculate a total summary score ranging from 5-20 (higher scores indicate better functional outcomes). The main focus will be on the total summary score, but scores from subscales will be explored as well.
Measured: 4 weeks
Short Form 36 (SF-36) Health Survey
The SF36 is a widely used questionnaire to measure general health-related quality of life across 8 domains (e.g. physical functioning, Energy/fatigue, Social functioning, etc). The score for each of the 8 domains ranges from 0 to 100, with greater scores indicating better health-related quality fo life in this domain.
Measured: 4 weeks
Mean blood pressure
Average mean blood pressure based on two resting blood pressure measurements. Systolic/diastolic blood pressures will be explored as well.
Measured: 4 weeks
Reactive hyperemia index
Based on a device called EndoPAT, which measures non-invasively bloodflow before, during, and after 5-minutes of occlusion to one arm.
Measured: 4 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted7 Apr 2023
- Study start16 May 2023
- Primary completion31 Oct 2026 (estimated)
- Study completion31 Oct 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Obstructive Sleep ApneaStudies of the same condition, open and under way.
- More trials run by University of California, San DiegoThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Randomized, double-blind, placebo-controlled, cross-over trial.
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of California, San Diego
- Sponsor type
- University, hospital or other
- Collaborators
- National Heart, Lung, and Blood Institute (NHLBI)
- Responsible party
- Principal investigator, Christopher Schmickl, University of California, San Diego
- Investigators
- Christopher N Schmickl, MD, PhD, Principal investigator, University of California, San Diego
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05804084
- Sponsor's protocol ID
- 802041
- Other IDs
- K23HL161336
- Acronym
- PANACEA
- Status last verified
- May 2026
- First submitted
- 27 Mar 2023
- Last updated
- 8 May 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 8 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Patient-centered and Neurocognitive Outcomes With Acetazolamide for Sleep Apnea
- ClinicalTrials.gov ID
- NCT05804084
- Acronym / sponsor ID
- PANACEA / 802041
- Conditions
- Obstructive Sleep Apnea
- Keywords
- Obstructive Sleep Apnea, OSA, Acetazolamide, Precision medicine
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 60 participants (estimated)
- Lead sponsor
- University of California, San DiegoUniversity, hospital or other
- Collaborators
- National Heart, Lung, and Blood Institute (NHLBI)
- Study start
- 16 May 2023 (actual)
- Primary completion
- 31 Oct 2026 (estimated)
- Study completion
- 31 Oct 2026 (estimated)
- First posted
- 7 Apr 2023 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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
Detailed description
The goal of this randomized, controlled, double-blind clinical trial is to compare the medication acetazolamide 500mg/day against placebo in adults who have at least moderate severe obstructive sleep apnea. The main questions this trial aims to answer are:
Is acetazolamide for 4 weeks more effective than placebo for treating obstructive sleep apnea? Is acetazolamide for 4 weeks more effective than placebo for improving neurocognitive function and quality of life? What are potential predictors and mechanisms of improvements with acetazolamide in sleep apnea, neurocognitive function and quality of life?
Participants will undergo the following activities:
- Eligibility screening (online or via phone; ~10min)
- Subjects who screen positive: in-person eligibility assessment (~1h) including a history, exam, blood testing, plus an overnight home sleep test
- Participants who are eligible: will come to the research lab (~15min) and be provided with a 4-week supply of the first study drug (i.e. acetazolamide or placebo) to be taken each night at home. Neither the researchers, nor the participants will know whether participants received acetazolamide or placebo. During this 4-week period, participants will wear a watch-sized activity tracker to measure their sleep amount and researchers will check in on participants weekly; at the end of the 4-week period participants are asked to come in for an overnight visit (~12h) which includes the following activities: general exam, questionnaires (e.g. quality of life), blood test, neurocognitive function tests, and an overnight sleep study to assess the severity of sleep apnea
Researchers will compare the effects of acetazolamide on sleep apnea severity, neurocognitive function and quality of life with the effects of placebo to see if acetazolamide may be an effective treatment for select patients with sleep apnea.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
- Model description
- Randomized, double-blind, placebo-controlled, cross-over trial.
| Arm | Type | Receives |
|---|---|---|
| Acetazolamide, then Placebo | Experimental | Drug: Acetazolamide, Drug: PlaceboSubjects 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 |
| Placebo, then Acetazolamide | Experimental | Drug: Acetazolamide, Drug: PlaceboSubjects 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 |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (3 listed)
- Age ≥18 years
- Body mass index ≤ 35 kg/m2
- Untreated moderate/severe OSA (AHI ≥15/h)
Key exclusion criteria (14 listed)
- 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)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| AcetazolamideAlso: DiamoxAcetazolamide tablet (encapsulated) | Drug | Acetazolamide, then Placebo, Placebo, then Acetazolamide |
| PlaceboSugar capsule manufactured to match encapsulated Acetazolamide | Drug | Acetazolamide, then Placebo, Placebo, then Acetazolamide |
Primary outcome
Apnea Hypopnea Index (AHI)
Time frame: 4 weeks
The AHI is a measure of sleep apnea severity and is defined as the number of apneas (no breathing for 10+ seconds) and hypopneas (reduced breathing for 10+ seconds associated with a >=3% desaturation or cortical arousal) per hour of sleep. Alternative definitions of the AHI will be explored as well (e.g. hypopneas based on 4% desaturations, or position/sleep-stage specific AHIs).
11 secondary outcomes
Hypoxic Burden (percent*minute/hour)
Time frame: 4 weeks
Overnight Memory Improvement (change in percentage points)
Time frame: 4 weeks
Cognitive function composite score
Time frame: 4 weeks
Response Speed
Time frame: 4 weeks
Patient-Reported Outcomes Measurement Information System (PROMIS) Sleep Disturbance (SDA) instrument
Time frame: 4 weeks
Patient-Reported Outcomes Measurement Information System (PROMIS) Sleep-Related Impairment (SRI) instrument
Time frame: 4 weeks
Epworth Sleepiness Scale (ESS) Score
Time frame: 4 weeks
Functional Outcomes of Sleep Questionnaire 10 (FOSQ-10)
Time frame: 4 weeks
Short Form 36 (SF-36) Health Survey
Time frame: 4 weeks
Mean blood pressure
Time frame: 4 weeks
Reactive hyperemia index
Time frame: 4 weeks
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 8 May 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Christopher N Schmickl, MD, PhD principal investigator
University of California, San Diego
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Acetazolamide in people with Obstructive Sleep Apnea, run by University of California, San Diego at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 14 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 8 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Pamela DeYoung, RPSGT (858 246 2183, sleepresearch@health.ucsd.edu), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Apnea Hypopnea Index (AHI) (time frame: 4 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 8 May 2026.