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

Utah System of Higher Education (USHE)

Status and phase: Completed; Phase 4

Conditions: Prophylaxis of Acute Mountain Sickness

Treatments: Drug: Low Dose Acetazolamide; Drug: Normal Dose Acetazolamide

Study type: Interventional

Funder types: Other

Identifiers

NCT01993667

50402

Details and patient eligibility

About

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

Full 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.

Enrollment: 130 patients

Sex: All

Ages: 18+ years old

Volunteers: Accepts Healthy Volunteers

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

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Double Blind

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130 participants in 2 patient groups

Acetazolamide normal dose

Active Comparator group

Description:

Experimental : Acetazolamide 125 mg twice daily

Treatment:

Drug: Normal Dose Acetazolamide

Acetazolamide low dose

Experimental group

Description:

Experimental: Acetazolamide 62.5 mg twice daily

Treatment:

Drug: Low Dose Acetazolamide