Comparison of Temazepam and Acetazolamide to Treat Difficulty Sleeping at High Altitude


More than 70% of visitors to high altitude suffer poor sleep. The present study seeks to answer the question: Which medication is associated with better sleep at high altitude: temazepam or acetazolamide? The investigators hypothesis is that one medication will be associated with higher subjective sleep scores than the other. The study will compare the sleep quality of 100 subjects as they take either temazepam or acetazolamide during a visit to high altitude.

Full Title of Study: “Treatment of High-altitude Sleep Disturbance: A Double-blind Comparison of Temazepam Versus Acetazolamide.”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Treatment
    • Masking: Triple (Participant, Care Provider, Investigator)
  • Study Primary Completion Date: July 2012

Detailed Description

Difficulty sleeping is very common with acute high altitude exposure. Sleep disturbances were reported by more than 70% of participants in acute mountain sickness pharmacologic treatment trials. Difficulty sleeping is one of the primary complaints of visitors to high altitude and some authors consider difficulty sleeping to be nearly universal at high altitudes. Acetazolamide, temazepam, zolpidem and zaleplon are all effective and safe in treating the acute insomnia of high altitude. No head-to-head trials have been performed to determine the best drug class for treatment of high altitude sleep disturbances. The purpose of this study is to compare temazepam and acetazolamide in the treatment of high altitude sleep disturbances. Such knowledge will benefit the hundreds of thousands of visitors to areas of high altitude throughout the world. The study will be a convenience sample of 100 trekkers in Manang, Nepal (elevation 11,500 feet). The study will only enroll trekkers who have gained more than 200 meters (650 feet) over the preceding 24 hours. Subject enrollment will take place from March 1, 2012, through May 30, 2012. One hundred subjects will be enrolled. All subjects will complete the study in Manang, Nepal. Once an individual decides to enroll in the study, they will be instructed on the risks of the study and informed consent will be obtained. Eligibility to participate will be verified. Each subject will be randomly assigned to take 125 mg of acetazolamide or 7.5 mg of temazepam by mouth immediately prior to going to bed. Each subject will only take one dose of the medication as part of the trial. Subjects will wear a pulse oximeter and an actigraph to bed. An actigraph is an accelerometer that is worn like a wrist watch. Actigraphs can sense and record movement and for this reason are often used in sleep studies to help measure sleep duration and quality. Study participants will keep a sleep log and will be asked to complete a Groningen Sleep Quality Questionnaire Survey and Lake Louise Acute Mountain Sickness questionnaire. Subjects will also complete a Stanford Sleepiness Scale every hour for eight hours. Through both objective and subjective measurement of sleep quality, this study is designed to determine which medication is associated with improved sleep at high altitude.


  • Drug: Temazepam
    • Temazepam 7.5mg capsule to be taken by mouth at bedtime for one night only.
  • Drug: Acetazolamide
    • Take Acetazolamide 125mg tablet by mouth at bedtime for one night only.

Arms, Groups and Cohorts

  • Active Comparator: Temazepam
    • 50 subjects are instructed to take 7.5mg temazepam by mouth prior to going to sleep for one night only.
  • Active Comparator: Acetazolamide
    • 50 subjects are instructed to take 125mg of acetazolamide by mouth prior to going to sleep one night only.

Clinical Trial Outcome Measures

Primary Measures

  • Global assessment of sleep quality using a 100mm visual analog scale
    • Time Frame: 1 day
    • The morning after taking the study medication, subjects will be asked: How would you rate last night’s sleep quality? They will mark their answer on a 100mm visual analog scale with 0mm representing ‘worst night of sleep ever’ and 100mm representing ‘best night of sleep ever’.
  • The Groningen Sleep Quality Questionnaire survey
    • Time Frame: 1 day
    • The Groningen Sleep Quality Questionnaire survey includes fifteen questions that describe sleep onset, sleep quality, awakenings, sleep duration, and wake up quality. Survey is completed by the subject.

Secondary Measures

  • Sleep Onset Latency
    • Time Frame: 1 day
    • The amount of time it takes the subject to fall asleep. Reported by the subject.
  • Total Sleep Duration
    • Time Frame: 1 day
    • The total amount of time that the subject slept. Recorded by the subject.
  • Time in Bed
    • Time Frame: 1 day
    • The amount of time the subject spent in bed. Recorded by the subject.
  • Number of Awakenings
    • Time Frame: 1 day
    • The number of times the subject woke up from sleep. Recorded by the subject.
  • Number of Awakenings to Urinate
    • Time Frame: 1 day
    • Number of time the subject woke up from sleep to use the restroom. Recorded by the subject.
  • Wake Time After Sleep Onset
    • Time Frame: 1 day
    • Amount of time the subject spent awake after falling asleep. Recorded by the subject.
  • Terminal Wakefulness
    • Time Frame: 1 day
    • The amount of time the subject spends in bed after waking up for the last time. Reported by the subject.
  • Global assessment of sleep depth
    • Time Frame: 1 day
    • Subjects will be asked to rate the depth of sleep on a 100mm visual analog scales.
  • Global assessment of drowsiness
    • Time Frame: 1 day
    • Subjects will be asked to assess their daytime drowsiness on a 100mm visual analog scale.
  • Stanford Sleepiness Scale scores
    • Time Frame: 1 day
    • During each of the eight hours after waking up, subjects will be asked to complete a Stanford Sleepiness Scale to measure how sleepy they are.
  • Lake Louis Acute Mountain Sickness delta score
    • Time Frame: 1 day
    • Subjects will be asked to fill out a Lake Louise Acute Mountain Sickness score at the beginning and end of study participation. The Lake Louise Acute Mountain Sickness score reflects on the severity of Acute Mountain Sickness being experienced by the subject. Scores consistent moderate or severe Acute Mountain Sickness will exclude subjects from participation in the study.
  • Mean O2 Saturation
    • Time Frame: 1 day
    • Study subjects will wear a pulse oximeter during the night that will record their oxygen saturation.
  • Proportion of time in periodic breathing
    • Time Frame: 1 day
    • Visitors to high altitude experience periodic breathing (alternating periods of increased and decreased respiratory rate) as the human body adjusts to the hypoxemia of high altitude. Both temazepam and acetazolamide have been shown to improve periodic breathing. Subjects will wear pulse oximeters. Data from the pulse oximeters will be used to calculate the amount of time that subjects spend in periodic breathing.
  • Number of desaturation events per hour
    • Time Frame: 1 day
    • Due to the periodic breathing that occurs at high altitude, there are frequent oxygen desaturations during sleep. Subjects will wear a pulse oximeter to determine how many time they experience a decline in their oxygen saturation during the night.
  • Number of awakenings per hour
    • Time Frame: 1 day
    • Subjects will wear an actigraph while they sleep. Actigraphs are small wristwatch-like devices that measure subtle movements while a subject is asleep. These movements are used to objectively describe awake and asleep periods.
  • Sleep Efficiency
    • Time Frame: 1 day
    • Subjects will wear an actigraph when they sleep. Actigraphs are small wristwatch-like devices that measure the subtle movements of a subject during the night and help objectively determine awake and asleep periods. Using data from the actigraph, one may calculate what percent of the night the subject was asleep (sleep efficiency).

Participating in This Clinical Trial

Inclusion Criteria

  • Trekkers on the Annapurna circuit – Must be in the process of ascent (> 200 meters over the previous 24 hours) – Must be willing to stay 2 nights in Manang, Nepal – Healthy adults, age 18-65 – Self-report of new difficulty sleeping over the previous two days Exclusion Criteria:
  • Recent (< 2 weeks) high altitude exposure (higher than 11, 500 feet or 3500 meters) – Current acute illness – Moderate to Severe Acute Mountain Sickness (Lake Louise AMS score > 4) – High Altitude Cerebral Edema – High Altitude Pulmonary Edema – Any pre-existing sleep disorders or sleep related condition including obstructive sleep apnea, morbid obesity (BMI > 40), restless leg syndrome, etc. – Any lung disease or condition affecting the lungs, including chronic obstructive pulmonary disease, asthma, cystic fibrosis, etc. – Congestive heart failure, pulmonary hypertension, or cardiomyopathy – Current oxygen use – Kidney disease – Liver disease – Pregnancy or breast feeding – Seizure disorder or other neurologic disorder – Glaucoma – Sulfa allergy – Acetazolamide allergy – Benzodiazepine allergy – Temazepam allergy – Currently on acetazolamide – Currently taking any benzodiazepines – Current medical treatment with any of the following: antidepressants, neuroleptics, anxiolytics, H1 antihistamines, barbiturates or hypnotics (including benzodiazepines or any other sleep aids). – Major psychiatric diagnosis (depression, anxiety, schizophrenia) – Recreational drug use – Caffeine con¬sumption > 3 cups of coffee/day – Alcohol consumption > 1 drink/day – Mental Retardation or Developmental Disabilities – Inability to provide informed consent
  • Gender Eligibility: All

    Minimum Age: 18 Years

    Maximum Age: 65 Years

    Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

    Investigator Details

    • Lead Sponsor
      • Massachusetts General Hospital
    • Provider of Information About this Clinical Study
      • Principal Investigator: N. Stuart Harris MD MFA, Director, MGH Wilderness Medicine Fellowship; Chief, Division of Wilderness Medicine, Department of Emergency Medicine, Massachusetts General Hospital; Assistant Professor of Surgery, Harvard Medical School – Massachusetts General Hospital
    • Overall Official(s)
      • Norman S Harris, MD, MFA, Principal Investigator, Massachusetts General Hospital


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