Effects of High AltitudePhase 4NCT01241513
Induced Changes in Ventilatory Responsiveness and Altitude Exposure
A Phase 4 study testing NAC in people with Effects of High Altitude and Hypoxia, run by United States Army Research Institute of Environmental Medicine at 1 site in United States.
Trial summary
The main purpose of this study is to determine if a drug (acetyl-cysteine or ACCY) can increase the amount of oxygen in your body at a high altitude of 11,500 feet. ACCY is approved by the Food and Drug Administration (FDA) as a treatment or antidote for Tylenol overdoses. Read more about this study
- Who is it for?
- Ages 18 to 39 yearsHealthy volunteers can take part
- Conditions the study is for
- Effects of High Altitude, Hypoxia, Inadequate or Impaired Breathing Pattern or Ventilation
- What is being tested?
- NAC
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 21 participants
- Where
- 1 siteUnited States
- Study dates
- 1 Nov 2010to 28 Feb 2013
- Phase
- Phase 4
- Are there results?
- Yes, posted in the registrySummary in the doctors' view
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 to 39 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- -
Who cannot join
- Volunteers with the following criteria will be EXCLUDED from participation:
- Less than 18 years of age Greater than 39 years of age Born at altitudes greater than 2134 m (7000 ft) Living in areas that are more than 1220 m (4,000 feet), or have traveled to areas that are more than 1220 m for more than a few days within the last 2 months.
- Abnormal [Hb]/Hct levels or presence of hemoglobin S Known allergies to sulfonamide derivatives Smokers who smoke more than 5 cigarettes per day Tobacco chewers If military, unable to pass the 2-mi run portion of the Army Physical Fitness Test, or equivalent If civilian, not currently running or exercising for at least 20 min/day, 3X/week in "aerobic" activities (e.g., running, biking. swimming, basketball, etc) If they do not want to walk or run multiple times for 1 to 3 hours on a treadmill Unable to meet the U.S. Army height/weight standards Not willing to sleep in bunk beds in a small room (8 feet by 8 feet) with 1 to 3 other volunteers (male and/or female) for 3 nights. If they are claustrophobic Women who are pregnant or planning to conceive during the study period Women who are not willing to take urine pregnancy tests Not willing to drink an eight ounce solution of diet soda that may contain ACCY up to three times per day and then not willing to suck on a peppermint mint right after drinking the solution.
- Taking medications that interfere with oxygen delivery and transport (Includes sedatives, sleeping aids, tranquilizers and any medication that depresses ventilation, diuretics, alpha and beta blockers) Evidence of any physical, mental, and/or medical conditions that would make the proposed studies relatively more hazardous. Evidence of prior HAPE or HACE diagnosis Evidence of apnea or other sleeping disorders Evidence of asthma If applicable, unwilling to stop taking all supplements for the two weeks of participation If applicable, all medications (prescription or over-the-counter) must be approved by the PI, and/or the OMSO.
Trial locations and contacts
1 site in 1 country.
About this study
Official title: Modulation of Oxygen Sensor Reactivity to Mimic Altitude Acclimatization
The main purpose of this study is to determine if a drug (acetyl-cysteine or ACCY) can increase the amount of oxygen in your body at a high altitude of 11,500 feet. ACCY is approved by the Food and Drug Administration (FDA) as a treatment or antidote for Tylenol overdoses. Other forms of ACCY are also sold over-the-counter as nutritional supplements. In this study, the FDA-approved form of ACCY will be used "off-label" (meaning in a way not approved by the FDA).
This study is being conducted by researchers from the United States Army Research Institute of Environmental Medicine (USARIEM). The study will take place in the Altitude Chamber located in the basement of USARIEM. A total of approximately 30 volunteers (men and women, military and civilians) will take part in the study. They can expect to be in the study for a minimum of a few hours each day for two weeks.
The investigators hypothesize that ACCY will improve ventilation and oxygenation while at altitude.
Read the detailed description
This study will determine if modulating reduction/oxidation (redox) status through a temporary increase in the blood ratio of reduced-to-oxidized glutathione (i.e., GSH/GSSG) will increase carotid body chemosensitivity and thus increase ventilation and arterial oxygen saturation (SaO2) during 32 hours of hypobaric hypoxia exposure to 3500 m (11,500 feet). To that end, the study will use an FDA-approved oral suspension form of acetylcysteine (ACCY) to modulate blood redox status under controlled conditions in the Hypobaric Chamber Facility at the USARIEM. Up to 30 healthy, active-duty military personnel or civilians from the local area will be recruited. Two independent treatment groups (placebo and ACCY; up to 15 in each group) will be assessed at sea level and altitude using a between-group experimental design. The two groups will be matched as closely as possible by age, ventilation, fitness, and gender prior to treatment assignment. Neither the staff nor the volunteers will know the treatment received by the groups until the study is completed. Included will be only those men and women who: are 18 to 39 years old, were born at altitudes below 2100 m (7000 feet), are not taking medications that interfere with oxygen delivery and transport (includes sedatives, sleeping aids, tranquilizers and any medication that depresses ventilation, diuretics, alpha and beta blockers); and have no evidence of any physical, mental, and/or medical conditions that would make the proposed study relatively more hazardous. All volunteers will participate over the two-week long study period in multiple standardized assessments that include resting (e.g., resting ventilation, SaO2, questionnaires), sleeping (e.g., heart rate, SaO2) and exercise (e.g., steady-state and time-trial performance, SaO2) measurements. The potential risks to test volunteers include the risks associated with hypobaric hypoxia exposure (e.g., acute mountain sickness [AMS; headache, nausea, insomnia]) and those associated with exercise (e.g., acute musculoskeletal strains and sprains, blisters). The investigators are not aware of any studies reporting problems during oral administration of ACCY in the doses or duration to be used in the present study. There are no direct benefits to the volunteers, except the knowledge of how well they performed at altitude and on the tests in which they participated. If the use of ACCY proves effective at altitude, then soldiers deployed to altitude in the future may have a means to beneficially increase ventilation and SaO2 in a manner similar to that experienced during natural altitude acclimatization.
- Conditions
- Effects of High Altitude, Hypoxia, Inadequate or Impaired Breathing Pattern or Ventilation, Abnormal Blood Oxygen Pressure
- Being tested
- NAC, Placebo
- Keywords
- glutathione, redox status, carotid body chemosensitivity, ventilation
- Medical subject headings
- Altitude Sickness, Hypoxia, Respiratory Aspiration
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
NACDrug
Also called NAC Accy
NAC provided to determine if beneficial at altitude
PlaceboDrug
Placebo
| Study group | Role | What they receive |
|---|---|---|
| N-acetyl-L-Cysteine | Experimental | N-Acetyl-L-Cysteine Receives: Drug: NAC |
| Placebo | Placebo comparator | placebo Receives: Drug: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Arterial Oxygen Saturation
Finger Pulse Oximetry to measure arterial oxygen saturation
Measured: Day 4 of treatment during acute altitude exposure
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Nov 2010 (estimated)
- Study start1 Nov 2010
- Primary completionMay 2011
- Study completion28 Feb 2013
Why it stopped: Results of preliminary analyses showed no reason to continue the study
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Posted resultsParticipant flow, outcome measures and adverse events reported by the sponsor.
- Other trials for Effects of High AltitudeStudies of the same condition, open and under way.
- 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 4
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind
- Who is masked
- Participant, Care provider, Outcomes assessor
- Enrolment
- 21 participants (actual)
Sponsor and investigators
- Lead sponsor
- United States Army Research Institute of Environmental Medicine
- Sponsor type
- US federal agency
- Responsible party
- Sponsor
- Investigators
- Charles S Fulco, ScD, Principal investigator, United States Army Research Institute of Environmental Medicine
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT01241513
- Sponsor's protocol ID
- H10-13
- Status last verified
- Apr 2020
- First submitted
- 12 Nov 2010
- Last updated
- 30 Apr 2020
- Results posted
- Yes, on ClinicalTrials.gov
- Data monitoring committee
- Yes
Study at a glance
From the registry record, last updated by the sponsor on 30 Apr 2020. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Modulation of Oxygen Sensor Reactivity to Mimic Altitude Acclimatization
- ClinicalTrials.gov ID
- NCT01241513
- Acronym / sponsor ID
- H10-13
- Conditions
- Effects of High Altitude, Hypoxia, Inadequate or Impaired Breathing Pattern or Ventilation, Abnormal Blood Oxygen Pressure
- Keywords
- glutathione, redox status, carotid body chemosensitivity, ventilation
- Phase
- Phase 4
- Study type
- Interventional
- Recruitment status
- TerminatedReason stopped: Results of preliminary analyses showed no reason to continue the study
- Enrolment
- 21 participants (actual)
- Lead sponsor
- United States Army Research Institute of Environmental MedicineUS federal agency
- Study start
- 1 Nov 2010 (actual)
- Primary completion
- May 2011 (actual)
- Study completion
- 28 Feb 2013 (actual)
- First posted
- 16 Nov 2010 (estimated)
- Results
- Posted 18 May 2016
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The main purpose of this study is to determine if a drug (acetyl-cysteine or ACCY) can increase the amount of oxygen in your body at a high altitude of 11,500 feet. ACCY is approved by the Food and Drug Administration (FDA) as a treatment or antidote for Tylenol overdoses. Other forms of ACCY are also sold over-the-counter as nutritional supplements. In this study, the FDA-approved form of ACCY will be used "off-label" (meaning in a way not approved by the FDA).
This study is being conducted by researchers from the United States Army Research Institute of Environmental Medicine (USARIEM). The study will take place in the Altitude Chamber located in the basement of USARIEM. A total of approximately 30 volunteers (men and women, military and civilians) will take part in the study. They can expect to be in the study for a minimum of a few hours each day for two weeks.
The investigators hypothesize that ACCY will improve ventilation and oxygenation while at altitude.
Detailed description
This study will determine if modulating reduction/oxidation (redox) status through a temporary increase in the blood ratio of reduced-to-oxidized glutathione (i.e., GSH/GSSG) will increase carotid body chemosensitivity and thus increase ventilation and arterial oxygen saturation (SaO2) during 32 hours of hypobaric hypoxia exposure to 3500 m (11,500 feet). To that end, the study will use an FDA-approved oral suspension form of acetylcysteine (ACCY) to modulate blood redox status under controlled conditions in the Hypobaric Chamber Facility at the USARIEM. Up to 30 healthy, active-duty military personnel or civilians from the local area will be recruited. Two independent treatment groups (placebo and ACCY; up to 15 in each group) will be assessed at sea level and altitude using a between-group experimental design. The two groups will be matched as closely as possible by age, ventilation, fitness, and gender prior to treatment assignment. Neither the staff nor the volunteers will know the treatment received by the groups until the study is completed. Included will be only those men and women who: are 18 to 39 years old, were born at altitudes below 2100 m (7000 feet), are not taking medications that interfere with oxygen delivery and transport (includes sedatives, sleeping aids, tranquilizers and any medication that depresses ventilation, diuretics, alpha and beta blockers); and have no evidence of any physical, mental, and/or medical conditions that would make the proposed study relatively more hazardous. All volunteers will participate over the two-week long study period in multiple standardized assessments that include resting (e.g., resting ventilation, SaO2, questionnaires), sleeping (e.g., heart rate, SaO2) and exercise (e.g., steady-state and time-trial performance, SaO2) measurements. The potential risks to test volunteers include the risks associated with hypobaric hypoxia exposure (e.g., acute mountain sickness [AMS; headache, nausea, insomnia]) and those associated with exercise (e.g., acute musculoskeletal strains and sprains, blisters). The investigators are not aware of any studies reporting problems during oral administration of ACCY in the doses or duration to be used in the present study. There are no direct benefits to the volunteers, except the knowledge of how well they performed at altitude and on the tests in which they participated. If the use of ACCY proves effective at altitude, then soldiers deployed to altitude in the future may have a means to beneficially increase ventilation and SaO2 in a manner similar to that experienced during natural altitude acclimatization.
Study design
- Primary purpose
- Basic science
- Allocation
- Non-randomised
- Intervention model
- Parallel groups
- Masking
- Triple blind (participant, care provider, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| N-acetyl-L-Cysteine | Experimental | Drug: NACN-Acetyl-L-Cysteine |
| Placebo | Placebo comparator | Drug: Placeboplacebo |
Who may qualify
- Ages
- 18 to 39 years
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult
Key inclusion criteria (1 listed)
- -
Key exclusion criteria (4 listed)
- Volunteers with the following criteria will be EXCLUDED from participation:
- Less than 18 years of age Greater than 39 years of age Born at altitudes greater than 2134 m (7000 ft) Living in areas that are more than 1220 m (4,000 feet), or have traveled to areas that are more than 1220 m for more than a few days within the last 2 months.
- Abnormal [Hb]/Hct levels or presence of hemoglobin S Known allergies to sulfonamide derivatives Smokers who smoke more than 5 cigarettes per day Tobacco chewers If military, unable to pass the 2-mi run portion of the Army Physical Fitness Test, or equivalent If civilian, not currently running or exercising for at least 20 min/day, 3X/week in "aerobic" activities (e.g., running, biking. swimming, basketball, etc) If they do not want to walk or run multiple times for 1 to 3 hours on a treadmill Unable to meet the U.S. Army height/weight standards Not willing to sleep in bunk beds in a small room (8 feet by 8 feet) with 1 to 3 other volunteers (male and/or female) for 3 nights. If they are claustrophobic Women who are pregnant or planning to conceive during the study period Women who are not willing to take urine pregnancy tests Not willing to drink an eight ounce solution of diet soda that may contain ACCY up to three times per day and then not willing to suck on a peppermint mint right after drinking the solution.
- Taking medications that interfere with oxygen delivery and transport (Includes sedatives, sleeping aids, tranquilizers and any medication that depresses ventilation, diuretics, alpha and beta blockers) Evidence of any physical, mental, and/or medical conditions that would make the proposed studies relatively more hazardous. Evidence of prior HAPE or HACE diagnosis Evidence of apnea or other sleeping disorders Evidence of asthma If applicable, unwilling to stop taking all supplements for the two weeks of participation If applicable, all medications (prescription or over-the-counter) must be approved by the PI, and/or the OMSO.
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 |
|---|---|---|
| NACAlso: NAC AccyNAC provided to determine if beneficial at altitude | Drug | N-acetyl-L-Cysteine |
| PlaceboPlacebo | Drug | Placebo |
Primary outcome
Arterial Oxygen Saturation
Time frame: Day 4 of treatment during acute altitude exposure
Finger Pulse Oximetry to measure arterial oxygen saturation
Results and safety
Loading the posted results from ClinicalTrials.gov…
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 30 Apr 2020.
- Posted resultsParticipant flow, baseline, all outcome measures and adverse events.
Related trials for Effects of High Altitude
Not yet recruiting
Assessment of Six-minute Walking Distance 6MWD Between High Altitude HA vs. Sea Level LA in Patients With Pulmonary Arterial Hypertension PAH
Pulmonary Arterial Hypertension (PAH), Pulmonary Vascular Disease
Not yet recruiting
Assessment of Lung Function (Lufu) at Sea Level LA vs. High Altitude HA in Healthy Individuals
Healthy, Healthy Adult
Not yet recruiting
Assessment of Lung Function (Lufu) at Sea Level LA vs. High Altitude HA in Patients With Pulmonary Arterial Hypertension PAH
Pulmonary Arterial Hypertension (PAH), Pulmonary Vascular Disease
Not yet recruiting
Assessment of Total Pulmonary Resistance sPAP/CO Between Sea Level LA vs. High Altitude HA After Re-ascent in Healthy Individuals
High Altitude, Healthy
Not yet recruiting
Assessment of Heart Rate Variability HRV During Descent DE From 2850m to Sea Level and During Re-ascent A From Sea Level to 2850m in Healthy Individuals H
Healthy, Healthy Adult
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. This study is not recruiting at the moment.
Charles S Fulco, ScD principal investigator
United States Army Research Institute of Environmental Medicine
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 4 study testing NAC in people with Effects of High Altitude and Hypoxia, run by United States Army Research Institute of Environmental Medicine 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 1 inclusion and 4 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: stopped early, as of the sponsor's last update on 30 Apr 2020. 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. Some participants in this study may receive a placebo. 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 4 studies take place after a treatment is approved, to learn more about its long-term benefits and risks in everyday use.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
Yes. Results are posted in the registry (first posted 18 May 2016). A summary is in the For doctors view, and the full results are on ClinicalTrials.gov.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Arterial Oxygen Saturation (time frame: Day 4 of treatment during acute altitude exposure). 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 30 Apr 2020; AzTrials last refreshed its copy on 26 Oct 2026.