Order effective medication for preventing altitude sickness

Altitude sickness for many people already starts at 8,000 ft and can be a very unpleasant experience. Dr Felix offers prescription drug Diamox that raises urine production and changes blood acidity to improve your breathing.


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Prices exclude a prescription fee. This treatment requires a quick online consultation, which a doctor will review to determine if a prescription is appropriate.


What is altitude sickness?

Altitude sickness is also known as acute mountain sickness. It happens when you travel up to a high altitude - above 3,000m - without giving your body time to acclimatise to the surroundings. It happens because the air pressure decreases the further you are from the sea level, meaning less oxygen is getting to your heart and lungs. Acute mountain sickness feels similar to a hangover. 

What are the different types of altitude sickness?

There are three types of altitude sickness: Acute Mountain Sickness, High Altitude Pulmonary Oedema and High Altitude Cerebral Oedema. Acute mountain sickness is the first step, if left untreated it can quickly escalate into a more serious and potentially fatal form of altitude sickness. 

Why does altitude sickness happen?

Altitude sickness happens when you ascend to a high altitude too quickly. This does not allow the body to adjust to the height and the lower air pressure, causing difficulty getting adequate oxygen to the heart and lungs. If you are planning a trek or climb, it is important to prepare ahead of time as altitude sickness can affect anyone, even if you are an experienced climber. 

How dangerous is altitude sickness?

Altitude sickness can feel mild at first but it can escalate and be very dangerous and life threatening. It's important to be prepared for it and know how to seek assistance if required. Even if you are physically fit and a regular climber, this doesn't mean it won't happen to you.

Where can you get altitude sickness?

Altitude sickness occurs at heights of 2,500m or higher. You cannot get it in the UK as the tallest mountain is 1,345m which is Ben Nevis. Popular locations include: 

  • High altitude (2400-3658m)
    • Cochamba, Bolivia 
    • Bogota, Columbia 
    • Quito, Ecuador
    • Cuszco, Peru 
  • Very high altitude (3658-5500m)
    • La Paz, Boliva
    • Lhaza, Tibet
    • Everest Base Camp 
  • Extremely high altitude (5500-8848m)
    • Mt Everest 
    • Mt Kilimanjaro 


Altitude sickness symptoms

The symptoms of altitude sickness may feel similar to a hangover. They include: 

  • Nausea
  • Vomiting
  • Headaches 
  • Tiredness
  • Dizziness
  • Lack of appetite
  • Short of breath 

Symptoms usually get worse at night time and can escalate into a more serious form of altitude sickness if they are not attended to quickly. 

What are the warning signs of altitude sickness?

Altitude sickness does not usually occur right away. The symptoms will appear between 4-36 hours of being in a high altitude. The first signs include a headache, nausea, sickness, feeling dizzy and tired. If you have three or more of these symptoms this is known as acute mountain sickness which can escalate into more serious altitude sickness if it is not treated.

What is acute mountain sickness?

Acute mountain sickness is the least serious type of altitude sickness and is caused by going too high too fast without giving your body a chance to adjust. The symptoms resemble a mild hangover and include: 

  • Headache
  • Nausea
  • Vomiting 
  • Dizziness 
  • Tiredness

What is HACE (High altitude cerebral oedema)?

High altitude cerebral oedema is a more serious type of altitude sickness which occurs when acute mountain sickness accelerates. It causes swelling in the brain and statistically affects 1% of people travelling to high altitudes. The symptoms include: 

  • A severe headache
  • Loss of coordination 
  • Confusion 
  • Irrationality 
  • Vomiting

HACE can become fatal in a matter of hours. If any of these signs occur, descend from the high altitude immediately and seek help.

What is HAPE (High altitude pulmonary oedema)?

High altitude pulmonary oedema is the third type of altitude sickness. This happens due to fluid gathering in the lungs and poses a serious risk of death. Symptoms can come on quickly and include: 

  • Breathlessness
  • Marked fatigue
  • A fast pulse
  • A blue tinge to the skin 

Of all the types of altitude sickness, HAPE is the most likely to be fatal. If any symptoms occur then descent must happen immediately as this is a medical emergency.    


How to avoid altitude sickness

Altitude sickness can be avoided by ascending to high altitudes above 2,500m at a slow and steady pace. Avoid taking a flight which lands into areas of high altitude, instead take 2-3 days to get used to higher altitudes before travelling above heights of 2,500m. Other preventative measures include: 

  • Don't climb more than 300-500m in a day
  • Keep drinking water
  • Take a rest day every 3-4 days
  • Don't drink alcohol or smoke
  • Refrain from strenuous activity or exercise 24 hours before climbing 
  • Eat foods which are high in calories 
  • Take Acetazolamide to prevent symptoms 

How to treat altitude sickness

If you experience any symptoms of altitude sickness do not ignore them. Stop and rest, do not continue climbing for the next 24-48 hours. Painkillers can be taken for headaches and you can also take anti-sickness medicine if you experience nausea or vomiting. Stay hydrated and let any companions know how you are feeling, even if your symptoms feel mild. If altitude sickness escalates, confusion and denial of symptoms is common. If you do not feel any better after 24 hours then you must descend to a lower altitude. 

How can I acclimatise quickly?

Intermittent Hypoxic Training or taking Acetazolamide are two ways of helping your body to acclimatise quickly to high altitudes. IHT is interval training where you alternatively breathe in air with low oxygen and regular air through a mask. This gets your body used with lower levels of oxygen in the blood before you travel to a high altitude. Acetazolamide is a medication which you can access from a travel clinic or GP in preparation for your trip. However, these methods may not always be effective. Always stop and treat symptoms of altitude sickness if they occur.

What medication can help altitude sickness?

Acetazolamide can help to both prevent and treat altitude sickness. If you experience symptoms or feel unwell, the most important thing to do is rest and descend if you do not improve. The medication can help if you are unable to descend quickly.

What is IHT and can it help prevent altitude sickness?

Intermittent Hypoxic Training (IHT) involves practicing the intake of air with lower oxygen, alternating with normal air with a mask. The training increases your body's tolerance to lower oxygen levels in the blood. This is to help your body acclimatise to the low air pressure in high altitudes.  

Should I buy altitude sickness medication before I travel?

A medication called Acetazolamide can be prescribed by a GP or a travel clinic before you travel if it is deemed suitable for you. You should start taking it 2-3 days before beginning to climb to a high altitude. Acetazolamide is designed to help your body to acclimatise to high altitudes quicker. However, it may not always prevent altitude sickness. If you experience any symptoms then do not ignore them, always stop and rest. If they do not disappear within 24 hours then you should descend right away.

Why does hydration affect altitude sickness?

Dehydration can lead to altitude sickness. The humidity is higher than it would be at ground level and combined with the physical exertion produced during climbing, this means you will be sweating more. As a result, you need to drink a lot more water than you normally would in order to stay hydrated. Dehydration leads to headaches, fatigue and nausea. 

Side Effects

Complications of altitude sickness

Altitude sickness usually begins as acute mountain sickness. The symptoms can be mild, resembling a hangover. It's typical to experience headaches, nausea, tiredness, dizziness and vomiting. If this is not treated it can quickly escalate into more serious altitude sickness; HACE or HAPE. High altitude cerebral oedema (HACE) is the swelling of the brain, and HAPE, high altitude pulmonary oedema, is when fluid gathers in the lungs. Both these conditions can be fatal.


Can you get altitude sickness from flying?

Altitude sickness and cabin pressure are not quite the same thing. The symptoms can be similar, but the feeling of discomfort or popping in the ears is caused by the change of pressure in the cabin. This is not altitude sickness. It is possible to experience mild symptoms such as headaches, nausea, vomiting and dizziness.

Can you get altitude sickness from skydiving?

Altitude sickness is caused by ascending to a high altitude over 2,500m too quickly. Skydiving is a descent and you are not at a great height for long enough to get altitude sickness.  

Can you get altitude sickness from skiing?

Altitude sickness can occur during a skiing trip. This is usually triggered by travelling on a ski lift. Symptoms are usually mild given that you are not staying at a high altitude for very long.

How high do you have to be to get altitude sickness?

Altitude sickness can occur at 2,500m or above.

Who is at greatest risk of altitude sickness?

Altitude sickness can affect anyone. However, people with certain medical conditions are at greater risk. These include: 

  • Heart problems 
  • Lung problems
  • Diabetes 
  • Epilepsy 
  • Sickle cell disease

Does alcohol make altitude sickness more likely to happen?

Drinking alcohol can increase your risk of experiencing altitude sickness as it causes dehydration. It may also mask the symptoms and warning signs as the symptoms of altitude sickness resemble those of a hangover.

Can altitude sickness be affected by pre-existing medical conditions?

Pre-existing medical conditions do not necessarily make it more likely that you will experience altitude sickness but they can exacerbate symptoms or make it harder for your body to cope with it. If you have any of the following conditions, seek advice from a doctor before travelling to high altitudes: 

  • Heart or lung conditions including asthma 
  • Diabetes
  • Epilepsy 
  • Sickle cell disease 

Will certain medications make me more susceptible to altitude sickness?

If you are on any medications then seek advice from a doctor before travelling to high altitudes. 

How dangerous is altitude sickness if you’re pregnant?

Altitude sickness can be very dangerous if you are pregnant as the lowered oxygen levels in the blood will affect the amount of oxygen in the placenta, meaning the baby is getting less oxygen than usual. Pregnant women are advised not to travel to altitudes higher than 2,500m.  

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