Preventive altitude medicine exists, and the NHS says a GP or travel clinic may prescribe it if you have had altitude sickness before or must ascend quickly.
It is a backup to acclimatization, not a replacement: the NHS advises against jumping from below 1,200 metres to above 3,500 metres in a day. Symptoms typically start 6 to 10 hours after reaching altitude: headache, appetite loss, nausea. The rule that saves lives: a headache at altitude means stop climbing, and worsening symptoms mean descend. Severe altitude illness affecting brain or lungs is an emergency.
What to do
Common questions
What is altitude sickness medication?
There is a prescription option, and it is a plan-ahead conversation, not a pharmacy grab. The NHS says that if you have had altitude sickness before, or you are traveling to high altitude quickly, a GP or travel clinic may prescribe medicine to help prevent altitude sickness. The usual drug is acetazolamide (Diamox), taken starting before ascent. But the NHS is clear that medication is the backup, not the plan: the main prevention is acclimatization, which means ascending slowly. Its specific don'ts include not traveling from below 1,200 metres to above 3,500 metres in a single day, and not flying directly to a high-altitude destination and immediately exerting yourself. Know the symptom clock: altitude sickness symptoms usually start 6 to 10 hours after arrival at height, and the main ones are headache, loss of appetite, and feeling or being sick. The safety rule that matters more than any pill: headache at altitude plus worsening symptoms means stop ascending, and symptoms that get worse despite rest mean descend, because severe forms affect the brain and lungs and are life-threatening. Tell your trip companions the plan before you go, so nobody talks you into pushing through a headache.