Descend to a lower altitude immediately
Stop ascending until symptoms fully resolve
Rest and avoid exertion
Drink fluids
Use acetaminophen or ibuprofen for headache if appropriate
Use oxygen if available
Consider acetazolamide for prevention or treatment if prescribed
Consider dexamethasone for severe symptoms if prescribed
Seek urgent medical care for confusion, trouble walking, shortness of breath at rest, or worsening symptoms
Use a portable hyperbaric bag if descent is not possible and available
Avoid alcohol, sleeping pills, and other sedatives
Acclimatize gradually on future ascents