HighCycle Study: Effect of Acetazolamide on Acute Mountain Sickness in Women Compared to Men
- Registration Number
- NCT06499727
- Lead Sponsor
- University of Zurich
- Brief Summary
Millions of people travel to high altitude for work or leisure activities and are exposed to reduced inspiratory oxygen partial pressure and hypoxemia that may lead to altitude illness, among which the most common form is acute mountain sickness (AMS). The main AMS symptoms are headache, malaise, weakness, and fatigue. Prospective studies have shown that 20-60% of newcomers at 2500-4000m develop AMS requiring them to take medications, while, at very high altitudes, AMS may progress to high altitude cerebral oedema. Whether women are more susceptible to AMS remains insufficiently understood since no prospective study controlled for sex hormones, use of hormone contraception or assessed menstrual cycle phase (MCP) at altitude. Therefore, women remain underrepresented and poorly characterized in high altitude studies. In addition, the efficacy and safety of 250 mg/day acetazolamide, the standard recommendation for AMS prevention, has never been compared between sexes, although, women have presumably higher acetazolamide plasma concentration due to lower blood volume. Given the known dose-dependent preventive but also side effects of acetazolamide and equal proportion of women and men among mountain travellers, there is an urgent need to conclusively quantify the efficacy and safety of pre-ventive acetazolamide therapy against AMS in women compared to men.
- Detailed Description
Not available
Recruitment & Eligibility
- Status
- RECRUITING
- Sex
- All
- Target Recruitment
- 270
- 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
- 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
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- PARALLEL
- Arm && Interventions
Group Intervention Description WOMEN - PLACEBO oral capsule Placebo Placebo (capsules identically looking as acetazolamide capsules; 1 in the morning, 1 in the evening), orally. Medication starts 24 hours before ascent to 3600 m until the morning after the second night at 3600 m. MEN - PLACEBO oral capsule Placebo Placebo (capsules identically looking as acetazolamide capsules; 1 in the morning, 1 in the evening), orally. Medication starts 24 hours before ascent to 3600 m until the morning after the second night at 3600 m. WOMEN - ACETAZOLAMIDE oral capsule Acetazolamide Acetazolamide 250 mg/day (capsules @125 mg; 1 in the morning, 1 in the evening), orally. Medication starts 24 hours before ascent to 3600 m until the morning after the second night at 3600 m. MEN - ACETAZOLAMIDE oral capsule Acetazolamide Acetazolamide 250 mg/day (capsules @125 mg; 1 in the morning, 1 in the evening), orally. Medication starts 24 hours before ascent to 3600 m until the morning after the second night at 3600 m.
- Primary Outcome Measures
Name Time Method Acute Mountain Sickness (AMS) Incidence, LLS 2018 Day 1 to 3 at 3600 m Sex-related difference between acetazolamide and placebo group in the incidence of AMS. AMS incidence will be defined as a Lake Louise Questionnaire version 2018 score of ≥3.
- Secondary Outcome Measures
Name Time Method Acute Mountain Sickness (AMS) Incidence, LLS 1993 Day 1 to 3 at 3600 m Sex-related difference between acetazolamide and placebo group in the incidence of AMS. AMS incidence will be defined as a Lake Louise Questionnaire version 1993 score of ≥3.
Acute Mountain Sickness (AMS) Severity, LLS 2018 Day 1 to 3 at 3600 m Sex-related difference between acetazolamide and placebo group in the AMS severity assessed by the Lake Louise Questionnaire version 2018.
Acute Mountain Sickness (AMS) Severity, LLS 1993 Day 1 to 3 at 3600 m Sex-related difference between acetazolamide and placebo group in the AMS severity assessed by the Lake Louise Questionnaire version 1993.
Drug-related side effects Day 1 to 3 at 3600 m Sex-related difference between acetazolamide and placebo group in the incidence and severity of medication side effects.
Arterial blood gases Day 2 at 760 m and day 2 at 3600 m Sex-related differences between acetazolamide and placebo group in the arterial blood gases (pH, PaO2, PaCO2, SaO2).
Acetazolamide plasma concentration Day 2 at 3600 m Sex-related differences between acetazolamide plasma concentration assessed by dried blood spots.
Hypoxic ventilatory response Day 2 at 760 m Sex-related difference in the hypoxic ventilatory response assessed under FiO2 of 0.115 and while cycling on a bicycle at 30% of predicted maximal work capacity.
Perceived pain visualization Day 1 to 3 at 3600 m Sex-related differences between acetazolamide and placebo group on perceived pain sensations, visualized by the SMaRT tablet app
Trial Locations
- Locations (1)
National Center for Cardiology and Internal Medicine
🇰🇬Bishkek, Kyrgyzstan