MEDICATIONS - Medicine for Mountaineering and Other Wilderness Activities - page 525

MEDICATIONS AFFECTING THE HEART, BLOOD VESSELS, AND
RESPIRATORY SYSTEM
Acetazolamide
Acetazolamide(Diamox®)inhibitstheenzymecarbonicanhydrase,whichcatalysesthe
reversible combination of carbon dioxide with water to form carbonic acid. This drug pro-
motes renal bicarbonate excretion and tends to reduce the respiratory alkalosis (increase in
blood pH) resulting from carbon dioxide loss at high altitudes as the result of faster and
deeper breathing.
Acetazolamidereducestheseverityofacutemountainsicknesssymptomsinindividuals
who must ascend from sea level to 12,000 to 14,000 feet (3700 to 4300 m) without ad-
equate time for acclimatization. It may not eliminate such symptoms entirely. In addition,
it promotes acclimatization.
A significant effect of acetazolamide on highaltitude pulmonary edema has not been
demonstrated.
Perhaps the greatest benefit from acetazolamide is relief of sleep problems at high alti-
tude. Elimination of episodes of severe hypoxia during sleep may be responsible for better
tolerance of high altitude during waking hours.
Precautions: Acetazolamide is a sulfonamide, although it does not have any antibac-
terial actions. Persons allergic to sulfonamides may be allergic to this drug.
Persons with liver or kidney disease should not be treated with acetazolamide, and the
drug should not be given during the last months of pregnancy or to nursing mothers.
Many individuals, perhaps most individuals, develop tingling sensations in the lips, fin-
gersorhands,toesorfeet,oroccasionally otherareas;blurringofvision;andalterations of
taste when taking this drug. These sensations disappear when the medication is stopped.
Dose: To promote sleep at high altitude, 62.5 to 250 mg orally at dinnertime.
Dexamethasone
Dexamethasone (Decadron and others), a synthetic glucocorticoid, is a potent steroid
that is used to treat a variety of disorders, but its value in the wilderness is quite limited.
The ability of this agent to reduce the edema associated with the spread of malignant tu-
mors from other organs to the brain led to therapeutic trials for high-altitude cerebral ed-
ema.Inthewilderness,itsvalueislargelylimitedtothetreatmentofsevereacutemountain
sickness and high-altitude cerebral edema.
Dexamethasone is as effective as acetazolamide for treating acute mountain sickness.
However, it does not promote acclimatization. Symptoms of acute mountain sickness re-
lieved by dexamethasone therapy recur when treatment is stopped. Dexamethasone is re-
commended only when symptoms have developed after preventive measures have been
neglectedorhavebeenimpossible,suchasinemergencyrescuesituations.However,recre-
ational skiers susceptible to acute mountain sickness at 8000 to 10,000 feet (2400 to 3000