Summary
Acetazolamide has reached the approved stage (maximum clinical phase 4) for at least one indication, so its use in Obstructive Sleep Apnoea (OSA) would be drug repurposing rather than first-in-human development. This does not mean it is approved for Obstructive Sleep Apnoea (OSA). ClinicalTrials.gov lists 8 registered trials linking Acetazolamide to Obstructive Sleep Apnoea (OSA): 2 are currently recruiting; 3 are active or not yet recruiting; 2 have completed; 1 is terminated, withdrawn, suspended or of unknown status. The most advanced is Phase 3 (NCT01499485). The largest enrolment is 560 participants (NCT06146101). Registration activity spans 2007 to 2026. The literature layer holds 4 publications for this pair: 4 clinical trial publications. Publication years run from 1995 to 2014. These are primary trial reports rather than syntheses, so results have not yet been pooled or graded independently.
The RepurpOS disease-intelligence file for Obstructive Sleep Apnea ranks 50 candidate therapeutics from Open Targets, ChEMBL, DGIdb and PubMed; only a minority carry direct clinical evidence, and this page covers one of those. Spontaneous remission context recorded for the condition: Spontaneous resolution without intervention rare; weight loss of 10-15% reduces AHI by 25-50% in obese patients; mild OSA may resolve with weight loss; moderate-severe OSA essentially irreversible without intervention.
Evidence table
| Evidence tier | A · Strong |
|---|---|
| Evidence score | 53.0 (trials 25.0, literature 8.0, tier 15, approved bonus 5.0) |
| Registered trials | 8 total: 2 recruiting, 3 active / not yet recruiting, 2 completed, 1 other |
| Linked publications | 4 (4 clinical trial publications) |
| Agent type | Drug (Small molecule) |
| Development stage (any indication) | Approved |
| Mechanism / class | Not recorded |
| Data sources | Open Targets, ChEMBL |
| Linked via biomarker / target | ALDH1A2 |
How the evidence score is calculated
- Each registered trial scores by status (recruiting / active / enrolling 3, completed 2.5, not yet recruiting 2, unknown 1, terminated / withdrawn / suspended 0.5) plus a phase bonus (phase 3-4 +2, phase 2 +1, phase 1 +0.5). The trial component is capped at 30.
- Each literature item scores by design (Cochrane review 5, meta-analysis 4, systematic review 3, RCT 3, clinical trial publication 2, curated reference 1.5, other PubMed record 1). The literature component is capped at 30.
- The existing evidence tier adds 15 (A / Strong), 10 (B / Moderate), 5 (C / Preliminary) or 0 (D / Anecdotal).
- Agents approved for any indication (max clinical phase 4) add 5, because an approved agent has an established safety profile that lowers the barrier to repurposing trials.
- The score ranks what has been studied, not what works. It does not read effect sizes or directions of effect.
Registered clinical trials
| NCT ID | Title | Status | Phase | Enrolment |
|---|---|---|---|---|
| NCT01499485 | Treatment of Metabolic Alkalosis With Acetazolamide. Effect on the Length of Mechanical Ventilation. 2011 | completed | Phase 3 | 140 |
| NCT06776432 | Safety and Efficacy Study of Sivopixant, Acetazolamide and SASS-001 in Sleep Apnea 2025 | active, not recruiting | Phase 2 | 60 |
| NCT07635563 | DReAMzz- Dronabinol and Acetazolamide Medication for Sleep Apnea (ZZ). Dose Confirmation Crossover Study for IHL-42X in Subjects With Obstructive Sleep Apnea. 2026 | not yet recruiting | Phase 2 | 120 |
| NCT05804084 | Patient-centered and Neurocognitive Outcomes With Acetazolamide for Sleep Apnea 2023 | recruiting | Phase 2 | 60 |
| NCT05857384 | Bioavailability, Bioequivalence and Tolerability of IHL-42X Compared to the Reference Drugs 2023 | completed | Phase 1 | 125 |
| NCT06146101 | RePOSA-Revealing the Efficacy of IHL-42X Use in Patients With OSA 2024 | active, not recruiting | PHASE2, PHASE3 | 560 |
| NCT05293600 | Rescue Pharmacotherapy for OSA 2023 | recruiting | PHASE1, PHASE2 | 70 |
| NCT00108602 | Sleep Apnea: Mechanism and Cerebrovascular Consequences 2007 | withdrawn | Not applicable | — |
Published literature
- Clinical trial publication Impact of acetazolamide and CPAP on cortical activity in obstructive sleep apnea patientsStadelmann K, Latshang TD, Nussbaumer-Ochsner Y et al. · PloS one · 2014 · PMID 24710341
- Clinical trial publication Effect of acetazolamide and autoCPAP therapy on breathing disturbances among patients with obstructive sleep apnea syndrome who travel to altitude: a randomized controlled trialLatshang TD, Nussbaumer-Ochsner Y, Henn RM et al. · JAMA · 2012 · PMID 23232895
- Clinical trial publication Patients with obstructive sleep apnea syndrome benefit from acetazolamide during an altitude sojourn: a randomized, placebo-controlled, double-blind trialNussbaumer-Ochsner Y, Latshang TD, Ulrich S et al. · Chest · 2012 · PMID 21659435
- Clinical trial publication [Treatment of obstructive sleep apnea syndrome with a mandibular positioning device and other nonsurgical modalities]Sakakibara H, Umemoto M, Kuwahara M et al. · Nihon Kyobu Shikkan Gakkai zasshi · 1995 · PMID 8752487
Mechanism and notes
No mechanism of action is recorded for this pair in the source databases.
OSMF's existing evidence tier for this pair is A (Strong), derived from the strength of the disease association recorded in Open Targets and ChEMBL, in this case via the biomarker or target ALDH1A2. The tier describes how well the drug-disease link is documented, not how well the drug works.
Frequently asked questions
Is Acetazolamide approved for Obstructive Sleep Apnoea (OSA)?
Acetazolamide has reached the approved stage (maximum clinical phase 4) for at least one indication, so its use in Obstructive Sleep Apnoea (OSA) would be drug repurposing rather than first-in-human development. This does not mean it is approved for Obstructive Sleep Apnoea (OSA). Approval status for the specific indication should always be confirmed with the relevant regulator and prescribing information.
Is Acetazolamide in clinical trials for Obstructive Sleep Apnoea (OSA)?
ClinicalTrials.gov lists 8 registered trials linking Acetazolamide to Obstructive Sleep Apnoea (OSA): 2 are currently recruiting; 3 are active or not yet recruiting; 2 have completed; 1 is terminated, withdrawn, suspended or of unknown status. The most advanced is Phase 3 (NCT01499485). The largest enrolment is 560 participants (NCT06146101). Registration activity spans 2007 to 2026.
What does the evidence show for Acetazolamide in Obstructive Sleep Apnoea (OSA)?
Acetazolamide has 2 completed trials and 4 linked publications for Obstructive Sleep Apnoea (OSA). Completed trials may or may not have posted results; follow the NCT links to check. OSMF's existing evidence tier for this pair is A (Strong), derived from the strength of the disease association recorded in Open Targets and ChEMBL, in this case via the biomarker or target ALDH1A2. The tier describes how well the drug-disease link is documented, not how well the drug works.
Cite this page
Data: ClinicalTrials.gov, PubMed, Open Targets, ChEMBL, DGIdb and the OSMF therapeutic agent database. Last updated 2026-07-06. Page built 2026-10-07.