Acetazolamide for the Prevention of High Altitude Illness: a Comparison of Dosing

This is a phase 4, randomized, double-blinded interventional trial comparing alternative doses of Acetazolamide for the prevention of High Altitude Illness.

Study Overview

• Status: Completed
• Conditions: Prophylaxis of Acute Mountain Sickness
• Intervention / Treatment: Drug: Normal Dose Acetazolamide; Drug: Low Dose Acetazolamide

Detailed Description

Acetazolamide, or Diamox, is the standard medical prophylaxis agent for high altitude illness. The medication is effective in preventing acute mountain sickness (AMS), high altitude pulmonary edema (HAPE), and high altitude cerebral edema (HACE). Its mechanism is via inhibition of the carbonic anhydrase enzyme which counteracts the respiratory alkalosis which occurs during ascent to altitude. It facilitates the excretion of bicarbonate in the urine. As a result, acetazolamide hastens acclimatization and helps prevent high altitude disorders.

Current recommended dosing is 125 mg, orally twice daily, started 24 hours prior to ascending in elevation. Side effects include tingling of the fingers and toes and perioral numbness which may be erroneously interpreted as stroke symptoms. Since acetazolamide is a mild diuretic, frequent micturition may occur leading to interruption of daytime activities as well as broken sleep. These effects can affect safety at high altitude. Acetazolamide is normally discontinued 2 days after the user has reached their highest elevation or a plateau in elevation.

A lower dose may be just as effective in preventing high altitude illnesses while preventing the disconcerting side effects resulting from its use. A smaller dose has not been studied, however. We will compare the common dose of 125 mg twice daily with a lower dose of 62.5 mg twice daily.

• Study Type: Interventional
• Enrollment (Actual): 130
• Phase: Phase 4

Contacts and Locations

Study Locations

• United States
  • Utah
    • Salt Lake City, Utah, United States, 84132
      • University of Utah Health Sciences Center

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years and older (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• 18 years or older
• English or Indian speaking
• Mountaineers or trekkers who plan to climb Mt. McKinley or trek to Base Camp on Mt. Everest

Exclusion Criteria:

• Low sodium and/potassium blood serum levels
• Kidney disease or dysfunction
• Liver disease, dysfunction, or cirrhosis
• Suprarenal gland failure or dysfunction
• Hyperchloremic acidosis
• Angle-closure glaucoma
• Taking high dose aspirin (over 325 mg/day)
• Any reaction to sulfa drugs or acetazolamide
• Pregnant or lactating women

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Double

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Acetazolamide normal dose; Experimental : Acetazolamide 125 mg twice daily	Drug: Normal Dose Acetazolamide; Administration of normal dose acetazolamide; Other Names: Diamox
Experimental: Acetazolamide low dose; Experimental: Acetazolamide 62.5 mg twice daily	Drug: Low Dose Acetazolamide; Administration of low dose acetazolamide; Other Names: Diamox

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With Acute Mountain Sickness as Measured by the Lake Louise Score	Lake Louise Score, A total score of 3 to 5 indicates mild AMS. A score of 6 or more signifies severe AMS. Minimum value - 0, Maximum = 15	12 days

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Number of Participants With Side Effects	The typical side effects of acetazolamide will be measured daily (paresthesias of fingers and toes, change in urination frequency, and change in taste of beverages). The side effect questionnaire included the following questions: In the past 12 h, have you experienced the following symptoms: Tingling of toes? Tingling of fingers? Increase in urination? Taste change of beverages? Symptoms were self-reported and rated on a 0-5 scale (0=none, 5=maximum)	12 days

Collaborators and Investigators

• Sponsor: University of Utah
• Investigators: Principal Investigator: McIntosh Scott, MD, University of Utah

Study record dates

Study Major Dates

• Study Start: March 1, 2012
• Primary Completion (Actual): November 1, 2016
• Study Completion (Actual): November 1, 2016

Study Registration Dates

• First Submitted: November 12, 2013
• First Submitted That Met QC Criteria: November 18, 2013
• First Posted (Estimate): November 25, 2013

Study Record Updates

• Last Update Posted (Actual): January 29, 2019
• Last Update Submitted That Met QC Criteria: January 10, 2019
• Last Verified: January 1, 2019

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Respiratory Tract Diseases; Respiration Disorders; Altitude Sickness; Physiological Effects of Drugs; Molecular Mechanisms of Pharmacological Action; Enzyme Inhibitors; Carbonic Anhydrase Inhibitors; Natriuretic Agents; Diuretics; Anticonvulsants; Acetazolamide
• Other Study ID Numbers: 50402