NCT07118462 HighCycle Study: Acetazolamide, High Altitude and Plasma Volume
| NCT ID | NCT07118462 |
| Status | Recruiting |
| Phase | Phase 4 |
| Sponsor | Centre d'Expertise sur l'Altitude EXALT |
| Condition | High Altitude Effects |
| Study Type | INTERVENTIONAL |
| Enrollment | 270 participants |
| Start Date | 2024-07-15 |
| Primary Completion | 2025-12-31 |
Eligibility & Interventions
Eligibility Fast-Check
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What to Expect as a Participant
You will actively receive the study intervention — which may be a drug, biologic, device, or procedure.
Phase 4 studies follow an already-approved treatment in real-world conditions to monitor long-term safety and effectiveness.
This trial targets 270 participants in total. It began in 2024-07-15 with a primary completion date of 2025-12-31.
⚠ This information is for research awareness only. Always consult your physician before joining any clinical trial. Participation is voluntary and you may withdraw at any time.
Brief Summary
Each year, millions of people living at low altitude (\< 1,000 m) travel to high altitude (≥ 2,500 m) for work, tourism, or sports activities. These individuals are exposed to hypobaric hypoxia, which can trigger acute mountain sickness (AMS)-the most common form of altitude-related illness. Therefore, understanding the physiological responses to hypoxia that allow acclimatization, as well as the pathophysiology of acute mountain sickness, is of primary importance. The hematological response to high-altitude exposure initially includes a reduction in plasma volume (PV), leading to an early increase in hemoglobin concentration within the first 24 hours. In contrast, an increase in hemoglobin mass requires several weeks at high altitude. Recent well-controlled physiological studies conducted in hypobaric chambers have demonstrated that this hypoxia-induced PV contraction results from fluid redistribution from the intravascular to the extravascular compartment, rather than from water loss due to increased diuresis. Prophylaxis of AMS is primarily based on the administration of 250 mg/day of acetazolamide (ACZ), a carbonic anhydrase inhibitor with a mild diuretic effect. Acetazolamide induces metabolic acidosis, which stimulates ventilation and thereby improves oxygenation. The effect of prophylactic ACZ use during high-altitude exposure on PV in lowlanders remains unknown: it is unclear whether ACZ leads to a greater reduction in PV due to its diuretic effect, or to a smaller hypoxia-induced PV contraction as a result of improved oxygenation induced by increased ventilation.
Eligibility Criteria
Inclusion Criteria: * Healthy, non-smoking men and women, age 18-44 years, without any disease and need of regular medication (including oral contraceptives). * BMI \>18 kg/m2 and \<30 kg/m2. * Born, raised and currently living at altitudes \<1000 m. * Written informed consent. * Premenopausal women with an eumenorrheic cycle. Exclusion Criteria: * Other types of contraceptvies (contraceptives (hormonal intrauterine device, vaginal ring, subcutaneous injections or implants, among others). * Pregnancy or nursing * Anaemic (haemoglobin concentration \<10g/dl). * Any altitude trip \<4 weks before the study. * Allergy to acetazolamide and other sulfonamides.
Contact & Investigator
Michael Furian, Prof. Dr.
STUDY CHAIR
University of Zurich
Frequently Asked Questions
Who can join the NCT07118462 clinical trial?
This trial is open to participants of all sexes, aged 18 Years or older, up to 44 Years, studying High Altitude Effects. Full inclusion and exclusion criteria are listed in the Eligibility Criteria section. Always confirm your eligibility with the research team before applying.
What phase is the NCT07118462 trial and what does that mean for participants?
Phase 4 studies are conducted after a treatment has been approved. They monitor long-term safety and real-world effectiveness in a broader patient population.
Is NCT07118462 currently recruiting?
Yes, NCT07118462 is actively recruiting participants. Contact the research team at BChampigneulle@chu-grenoble.fr for enrollment information.
Where is the NCT07118462 trial being conducted?
This trial is being conducted at Bishkek, Kyrgyzstan.
Who is sponsoring the NCT07118462 clinical trial?
NCT07118462 is sponsored by Centre d'Expertise sur l'Altitude EXALT. The principal investigator is Michael Furian, Prof. Dr. at University of Zurich. The trial plans to enroll 270 participants.