Altitude Sickness: UK Online Doctor Prevention with Acetazolamide
Educational information — not medical advice.
This article was prepared by the OnlineDoctor24 editorial team and reviewed for factual accuracy against UK clinical guidance (NHS and NICE). It is not written by a doctor and does not replace personal medical advice. For symptoms specific to you, book an online doctor consultation.
Key points
- Altitude sickness can affect anyone above 2,500m.
- Slow ascent ('climb high, sleep low') is the best prevention.
- Acetazolamide (Diamox) reduces risk and severity.
- Severe symptoms (HACE, HAPE) are life-threatening — descend immediately.
What is AMS?
Acute mountain sickness causes headache, nausea, fatigue and poor sleep — usually starting 6–24 hours after rapid ascent.
Prevention
- Ascend gradually above 2,500m — no more than 300–500m sleeping altitude gain per day.
- Rest day every 1,000m.
- Hydrate well.
- Avoid alcohol/sedatives early.
- Acetazolamide 125–250mg twice daily, starting 1 day before ascent.
Treatment
- Mild AMS: rest, hydrate, paracetamol, anti-emetic, acetazolamide.
- Don't ascend further until symptoms resolve.
- Severe (HACE/HAPE): descend immediately, oxygen, dexamethasone (HACE), nifedipine (HAPE).
Online consultation
A UK online GP can prescribe Diamox and dexamethasone for trek/expedition use after a brief consultation.
Red flags — when to seek urgent help
Call 999 or go to A&E if you experience any of the following:
- Confusion, ataxia (HACE)
- Severe breathlessness at rest, frothy sputum (HAPE)
- Symptoms not improving despite stopping ascent
Frequently asked questions
Common questions UK patients ask about altitude sickness.
How an online doctor can help
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This article is for general information only and does not replace personal medical advice from a qualified doctor. Content is reviewed against UK NHS and NICE guidance by the OnlineDoctor24 editorial team and is not authored by a medical doctor. If your symptoms worsen or you are unsure, please book a consultation with a GMC-registered GP.
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