Condition category
Signs and Symptoms
Date applied
Date assigned
Last edited
Prospectively registered
Overall trial status
Recruitment status
No longer recruiting

Plain English Summary

Not provided at time of registration

Trial website

Contact information



Primary contact

Dr Buddha Basnyat


Contact details

Nepal International Clinic
Lal Durbar
GPO BOX 3596

Additional identifiers

EudraCT number number

Protocol/serial number


Study information

Scientific title



Study hypothesis

Acute Mountain Sickness (AMS) is like a hangover (headache, nausea and tiredness being prominent features) that may manifest at altitudes greater than 2600 m when people ascend too high too fast.

This is a study to ascertain the benefit of spironolactone (aldactone), a water pill, in the prevention of AMS which comprises of headache, nausea and tiredness at altitude greater than 2700 m. Acetazolamide (Diamox®) which we know works for the prevention of AMS will be compared with spironolactone and a placebo or a sugar pill.

Spironolactone will prevent AMS.

Ethics approval

Added 24/11/2008: OXTREC approval on 07/10/2008 for the study (031 07).

Study design

Randomised, double blind, placebo controlled trial

Primary study design


Secondary study design

Randomised controlled trial

Trial setting

Not specified

Trial type


Patient information sheet

Not available in web format, please use the contact details below to request a patient information sheet


Acute mountain sickness


This is a prospective three armed, double blind, randomised, placebo controlled trial. Computer generated randomisation of spironolatone, acetazolamide and placebo will be carried out. After consent is obtained, participants will receive a four days supply of either spironolactone 50 mg twice daily (bid), acetazolamide 250 mg bid or visually matched placebo bid. Trekkers will be enrolled in the study and baseline measurements done at Pheriche (4300 m) and reassessed after their arrival at the endpoint in Lobuje (5000 m). The reassessment will take place at least 36 hours to a maximum of 96 hours (4 days) after taking the study drug.

Assessments and measurements will be made in these areas prior to and after ascension on the study drug:
1. Lake Louise Questionnaire
2. Oxygen saturation via pulse oximetry

The approach to Everest Base Camp provides a unique study population for the following reasons:
1. Large numbers of recently arrived (non-acclimated) trekkers
2. Relatively homogenous population (gender, age, physical fitness, etc.) with relatively few pre-existing conditions
3. Linear population movement along the approach
4. Rapid and quantitatively large elevation change (about 700 m)

Data will also be collected on the demographics of the study population at the enrolment site. The study will not provide financial assistance in the event of the development of complications of being at high altitude.

Intervention type



Not Specified

Drug names

Spironolactone, acetazolamide

Primary outcome measures

Main outcome measure will be incidence of AMS measured by Lake Louise acute mountain sickness score (LLscore) greater than or equal to three with headache and at least one other symptom.

Outcomes will be measured at baseline (Pheriche 4300 m) and remeasured at Lobuje (5000 m). The reassessment will take place at least 36 hours to a maximum of 96 hours (four days) after taking the study drug.

Secondary outcome measures

1. Oxygen saturation measured by pulse oximeter
2. Severity of symptom (LLscore greater than five)
3. Incidence of headache and severity of headache

Outcomes will be measured at baseline (Pheriche 4300 m) and remeasured at Lobuje (5000 m). The reassessment will take place at least 36 hours to a maximum of 96 hours (four days) after taking the study drug.

Overall trial start date


Overall trial end date


Reason abandoned


Participant inclusion criteria

1. Healthy subjects between the ages of 18 and 65
2. Male or female
3. Non-Nepali
4. Without AMS or any concurrent illness
5. Not already taking acetazolamide or any other drug for the prevention of altitude illness

Subjects will be enrolled by study administrators en route directly to Everest Base Camp or Kala Patthar between the villages of Pheriche/Dingboche and Lobuje.

Participant type


Age group



Not Specified

Target number of participants

100 in each arm of the study

Participant exclusion criteria

1. Individuals not meeting inclusion criteria, including mild AMS (more than one mild symptom on the Lake Louise Questionnaire) or significantly depressed oxygen saturation (less than 75%)
2. Females known to be pregnant, or cannot exclude the possibility of being pregnant, or have missed menses by over seven days
3. Individuals with a known drug allergy to acetazolamide or other sulfa drugs
4. Individuals who are on Angiotensin-Converting Enzyme (ACE) inhibitors (like enalapril) or other diuretics like amiloride or triamterene, as concurrent administration with spironolactone can cause hyperkalemia
5. Individuals who have spent 24 hours at an altitude of 4500 metres/14,000 feet within the last nine days
6. Anyone known to have taken any of the following in the last two days:
6.1. Acetazolamide (Diamox®)
6.2. Steroids (dexamethasone, prednisone)
6.3. Theophylline
6.4. Diuretics (Lasix®)
7. Individuals who have a known intracranial space occupying lesion or a history of elevated intracranial pressure, (i.e. tumours, hydrocephalus, etc)
8. Lack of informed consent will obviously mandate exclusion

Recruitment start date


Recruitment end date



Countries of recruitment


Trial participating centre

Nepal International Clinic

Sponsor information


University of Oxford (UK)

Sponsor details

University Offices
Wellington Square
0X1 2JD
United Kingdom
+44 (0)1865 270143

Sponsor type




Funder type

Research organisation

Funder name

Oxford University Clinical Research Unit (Vietnam) (ref: HB0075)

Alternative name(s)

Funding Body Type

Funding Body Subtype


Results and Publications

Publication and dissemination plan

Not provided at time of registration

Intention to publish date

Participant level data

Not provided at time of registration

Results - basic reporting

Publication summary

Publication citations

Additional files

Editorial Notes