What medications are used to treat altitude sickness?

Medications for Altitude Sickness

Acetazolamide is the first-line prophylactic medication for altitude sickness, with a standard dose of 250 mg twice daily or 500 mg once daily. 1

Types of Altitude Sickness

• Altitude sickness can be categorized into cerebral forms (Acute Mountain Sickness [AMS] and High Altitude Cerebral Edema [HACE]) and pulmonary forms (High Altitude Pulmonary Edema [HAPE]) 2, 3
• Symptoms of mild to moderate AMS include headache, reduced appetite, nausea, vomiting, fatigue, weakness, dizziness, and poor sleep 4
• HACE and HAPE are life-threatening conditions that require immediate intervention 3

First-Line Medications

Acetazolamide

• Recommended as the primary prophylactic medication at 250 mg twice daily or 500 mg once daily 1
• Works as a carbonic anhydrase inhibitor causing mild diuresis and metabolic acidosis, which stimulates ventilation and improves oxygenation 1
• Should not be used as emergency therapy for established altitude sickness 2
• Increases arterial oxygen levels and reduces symptoms including headache, nausea, vomiting, and weakness 5

Dexamethasone

• Alternative when acetazolamide is contraindicated 1
• Effective for preventing and treating AMS at doses of 4 mg four times daily 4
• Should not be used for more than 2-3 days due to potential side effects 4
• Particularly effective for treating high altitude cerebral edema 3

Nifedipine

• Specifically recommended for prevention and treatment of HAPE 1, 3
• For patients with history of HAPE, nifedipine should be started with ascent and continued for 3-4 days after arrival at terminal altitude 6

Treatment Approaches

For Acute Mountain Sickness (AMS)

• Rest, descent or evacuation to lower altitude, and warmth are the main emergency measures 2
• Acetazolamide for prevention and early treatment 1, 5
• Dexamethasone for more severe symptoms 7
• Ibuprofen/naproxen can help with symptom management 2

For High Altitude Pulmonary Edema (HAPE)

• Immediate descent to lower altitude and supplemental oxygen are primary therapies 6
• Nifedipine is the medication of choice 3, 7
• Portable hyperbaric chambers can be used if immediate descent is not possible 2

For High Altitude Cerebral Edema (HACE)

• Immediate descent is critical 7
• Dexamethasone is the medication of choice 3
• Supplemental oxygen when available 7

Special Considerations

• Patients with cardiovascular disease should continue their pre-existing medications at high altitude 1
• When using acetazolamide with other diuretics, carefully monitor for dehydration and electrolyte imbalances 1
• PDE5 inhibitors (sildenafil, tadalafil) may be alternatives to nifedipine for HAPE prevention, but tadalafil has been associated with severe acute mountain sickness in some subjects 6

Prevention Strategies

• Slow, gradual ascent (300-600 m/day above 2500m) is the most effective prevention method 1
• Include rest days (one day for every 600-1200m gained) 1
• Avoid vigorous physical exertion before proper acclimatization 1
• Delay further ascent if initial symptoms appear 1

Common Pitfalls

• Underestimating the importance of gradual ascent and proper acclimatization 1
• Inadequate hydration can worsen symptoms 1
• Using acetazolamide as emergency therapy rather than as prophylaxis 2
• Continuing ascent despite symptoms of altitude sickness 1