Altitude sickness may occur in travelers who ascend rapidly to
altitudes greater than 2500 meters, including Cusco (3000 meters)
and Lake Titicaca (4000 meters). Acetazolamide is the drug of choice
to prevent altitude sickness. The usual dosage is 125 or 250 mg two
or three times daily starting 24 hours before ascent and continuing
for 48 hours after arrival at altitude. Possible side-effects
include increased urinary volume, numbness, tingling, nausea,
drowsiness, myopia and temporary impotence. Acetazolamide should not
be given to pregnant women or those with a history of sulfa allergy.
For those who cannot tolerate acetazolamide, the preferred
alternative is dexamethasone 4 mg taken four times daily. Unlike
acetazolamide, dexamethasone must be tapered gradually upon arrival
at altitude, since there is a risk that altitude sickness will occur
as the dosage is reduced.
Travel to high altitudes is generally not recommended for those with
a history of heart disease, lung disease, or sickle cell disease.
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