Planning a trekking holiday or a trip to destinations like Peru, Nepal, or the Himalayas is exciting, but altitude sickness is one aspect of preparation many travellers overlook. The higher you climb, the less oxygen is available, and for many people, that change causes symptoms ranging from a dull headache to something far more serious. Altitude sickness tablets can offer meaningful protection when taken correctly and with proper guidance.

At Shivas Pharmacy, we help travellers prepare for high-altitude trips through our travel clinic in Surrey. If you are planning a trip to altitude, contact us or book an appointment with our team.

What Is Altitude Sickness?

Altitude sickness, also known as acute mountain sickness (AMS), occurs when the body struggles to adapt to reduced oxygen levels at high elevation. It typically begins above 2,500 metres and can affect anyone regardless of age, fitness, or previous experience at altitude. Popular destinations such as Cusco in Peru, La Paz in Bolivia, and trekking routes in Nepal all sit at elevations where symptoms can develop quickly.

The most common symptoms include headache, fatigue, dizziness, nausea, and difficulty sleeping. In more serious cases, it can progress to high-altitude pulmonary oedema (HAPE) or high-altitude cerebral oedema (HACE), both of which are medical emergencies. You can read more on the NHS altitude sickness page.

Who Is At Risk Of Altitude Sickness?

Altitude sickness does not discriminate. Even highly fit, experienced travellers can be affected, and a previous trouble-free trip to altitude is no guarantee next time. Ascending too quickly, a history of previous altitude sickness, and travelling to very high elevations in a short time all increase your risk.

Common high-risk travel scenarios include:

■  Trekking in Nepal	■  Visiting Cusco or Machu Picchu	■  Climbing Kilimanjaro
■  Travelling to La Paz, Bolivia	■  Skiing at very high resorts	■  High-altitude safaris in East Africa

What Altitude Sickness Tablets Are Available?

The most widely used medication for preventing and treating altitude sickness is acetazolamide, sold under the brand name Diamox. It is a prescription-only medicine in the UK, meaning you will need to speak to a healthcare professional before obtaining it. Acetazolamide works by stimulating faster and deeper breathing, helping the body absorb more oxygen and speeding up acclimatisation.

It is typically started one to two days before ascending to altitude and continued for the first two days at elevation, or throughout the trip, depending on your itinerary. The standard adult dose is typically 125mg twice daily, though your prescriber may recommend up to 250mg twice daily depending on your itinerary and risk level.

Does Acetazolamide Prevent Altitude Sickness Completely?

Acetazolamide significantly reduces the risk and severity of altitude sickness, but is not a substitute for sensible acclimatisation. Ascending gradually, staying hydrated, and avoiding alcohol in the first few days at altitude all remain important alongside the medication.

Here is our guide explaining why visiting a travel vaccination clinic is important before you leave for your trip.

Side Effects And Who Should Avoid It

Like all medicines, acetazolamide can cause side effects. The most commonly reported are generally mild and manageable.

Common side effects to be aware of include:

• ✓  Increased urination, particularly in the first day or two
• ✓  Tingling in the hands, feet, or face
• ✓  Altered taste, particularly with carbonated drinks
• ✓  Mild nausea or stomach discomfort
• ✓  Increased sensitivity to sunlight

Acetazolamide should not be taken by people with a known allergy to sulfonamide medicines (note: your prescriber will assess your specific allergy history, as the degree of cross-reactivity varies), and requires careful consideration in those with kidney problems, liver conditions, or low sodium and potassium levels. It is also not recommended during pregnancy or breastfeeding. Always disclose your full medical history when requesting this medication.

Seek urgent medical attention if you experience:

• ⚠  Severe skin rash or blistering
• ⚠  Difficulty breathing or chest tightness
• ⚠  Signs of a serious allergic reaction
• ⚠  Worsening symptoms despite medication and descent

When Should You Start Taking Altitude Sickness Tablets?

Acetazolamide works best when started one to two days before reaching altitude, so organise your prescription well in advance of departure. A travel health consultation also lets you review your full itinerary and ensure you are prepared for every aspect of your trip.

What Else Should High-Altitude Travellers Consider?

Altitude sickness tablets are one part of a broader travel health plan. Depending on your destination, you may also need:

1. Hepatitis A vaccination
2. Typhoid vaccination
3. Rabies vaccination for remote trekking routes
4. Hepatitis B vaccination
5. Malaria prevention for lower-altitude sections of some routes
6. Japanese encephalitis in certain trekking areas in Asia

A full travel health consultation at Shivas Pharmacy will cover everything relevant to your destination and personal health history.

Get Your Altitude Sickness Tablets At Shivas Pharmacy

Whether you are heading to base camp, visiting a high-altitude city, or embarking on a bucket-list trek, getting the right advice and medication in advance makes a real difference. As a travel vaccination clinic in Surrey, Shivas Pharmacy can advise you on altitude sickness tablets and everything else your trip requires. Contact us today and book your appointment so we can help you travel safely and confidently.

This blog was written on behalf of Shivas Pharmacy by Pharmacy Mentor.