Our pharmacists at Chemitex Pharmacy, 332 Hornsey Road, provide altitude sickness treatment and prevention in Islington, with a private consultation, a personal risk check, and a same-day prescription for Diamox if it suits you.
Book online or call the pharmacy. Have your itinerary to hand, including the highest point you’ll reach and where you’ll sleep each night.
Your pharmacist reviews your route, ascent speed, medical history, and current medications to determine if tablets are suitable or if a slower ascent is better.
If approved, you’ll receive a private prescription for acetazolamide the same day, along with instructions on when to start, duration, and symptoms that require descent.
Altitude sickness is the body’s reaction to lower oxygen levels at height. It usually starts above 2,500 metres, and it can affect anyone, including fit, experienced trekkers.
The risk depends less on how high you go and more on how fast you get there. Flying straight into Cusco or La Paz carries a higher risk than walking up slowly over a week.
As you climb, air pressure drops. Each breath carries fewer oxygen molecules, even though the air is still 21% oxygen.
Your body can adapt, but it needs time. Problems start when you gain height faster than your body can adjust, especially when your sleeping altitude jumps by more than 500 metres in a day above 3,000 metres.
AMS normally appears 6 to 12 hours after arriving at a new height. A headache is the main sign, often with one or more of these:
Confusion, stumbling, breathlessness when resting, or a wet cough are emergency signs. Descend straight away and get medical help
Fitness does not protect you. Young, fit people often get it because they climb too quickly. Your risk is higher if you:
Most treks start at Lukla, around 2,860 metres. Base Camp sits at about 5,364 metres, and many trekkers push on to Kala Patthar at roughly 5,545 metres.
Cusco is about 3,400 metres high, and most visitors fly in from sea-level Lima. Machu Picchu is lower at around 2,430 metres, but the Inca Trail crosses a pass at about 4,215 metres.
El Alto Airport, serving La Paz, is over 4,000 metres. The Uyuni salt flats sit around 3,650 metres, and multi-day tours often climb close to 5,000 metres.
Uhuru Peak stands at 5,895 metres. Shorter five and six-day routes carry a high risk of AMS, which is why many climbers choose longer itineraries.
Leh in Ladakh is about 3,500 metres, and most visitors arrive by plane. Road passes and Karakoram treks regularly go beyond 5,000 metres.
Mount Toubkal reaches about 4,167 metres. Many visitors climb it over two days from Imlil, which is a fast ascent for the height gained.
Quito sits at about 2,850 metres, and Cotopaxi’s summit is close to 5,900 metres.
Lhasa is around 3,650 metres, and much of the plateau lies above 4,000 metres. Everest’s north base camp is roughly 5,150 metres.
We provide Diamox (acetazolamide), the most widely used altitude sickness medicine for preventing AMS. It helps your body adjust faster by making you breathe more deeply, especially at night.
It doesn’t replace a sensible ascent plan. Our pharmacist will confirm the right dose for your trip and health profile at your consultation.
Important Notice: Diamox (acetazolamide) is not officially approved in the UK for altitude sickness, despite being commonly recommended for this use.
Most side effects are mild and ease once you stop the course. The common ones are:
Stop taking it and seek urgent medical help if you have severe eye symptoms. This includes a sudden decrease in vision or eye pain, which may signal choroidal effusion or acute angle-closure glaucoma. Also, watch for a skin rash, side or back pain, or unusual bruising. Your pharmacist may suggest a short trial at home before you travel so you know how you react.
Acetazolamide isn’t suitable for everyone. We’ll check the following before issuing a prescription.
Acetazolamide must not be taken during pregnancy or while breastfeeding. It is strictly contraindicated.
Our altitude sickness service is for adults aged 18 and over. Children travelling to altitude should be assessed by their GP or a specialist travel clinic.
Acetazolamide is a sulphonamide. If you've reacted to sulpha antibiotics or similar medicines, you can't take it.
It's not suitable for people with serious kidney or liver problems. It can also affect salt and potassium levels in the blood.
Acetazolamide interacts with aspirin, lithium, sodium valproate, methotrexate, ciclosporin, sodium bicarbonate and methenamine. Bring a list of everything you take, including over-the-counter products.
People with Addison's disease, chronic closed-angle glaucoma, severe lung conditions (such as severe COPD or emphysema), or significant mental health disorders should not take it. Tell us about any long-term condition so we can check it's safe for you.
Book your consultation at least two to four weeks before you fly. That leaves time for a home trial dose and any travel vaccinations your destination needs.
If you’re short on time, we can still help. The prescription is issued the same day, as long as you’re suitable.
Our Independent Prescriber can assess more complex medical histories, so you’re less likely to be sent back to your GP.
High-altitude destinations in South America or Africa may require or recommend yellow fever cover depending on specific risk zones and transit countries. We can assess your risk and provide vaccinations and certificates in the same visit where appropriate.
If you’re suitable, you leave with your private prescription the same day, with clear instructions on starting and finishing your course.
We cover altitude medication, travel vaccinations and malaria tablets together, so you don’t need separate appointments before a big trek.
We look at your actual itinerary and sleeping heights and give practical ascent advice rather than a generic leaflet.
We’re close to Holloway Road and Finsbury Park stations, with online booking that fits around your working week.
Open six days a week, Chemitex Pharmacy is here to support your health. Call us, send an email, or visit our accessible pharmacy near Finsbury Park for all your healthcare needs.
Come and see why families in Islington have trusted Chemitex Pharmacy with their health for over 40 years. We're here for you.
Yes, parking is available right outside the pharmacy.
There's a bus stop just around the corner.
Trusted by generations of families in Islington.
Got some friendly and super quick travel vaccines here as I realised 5 days before travel. The pharmacist was soooo lovely and made the whole appointment easy. She was very informed and answered all my questions with confidence. Will be coming back for any future vaccine needs for sure as the price was much cheaper than the other ones in the area
I came into the chemist on Friday and I was very impressed by your colleague Fiona and how skilled she is with customers, particularly those who are vulnerable. She offered reassurance, was informative, and showed kindness and patience. She is an asset to your business.
Great little local pharmacy with wide selection and convenient hours, always has what I need in stock. Great customer service and advice from a lovely bubbly young woman who works on the till. Would recommend.
I needed to get a Covid and Flu vaccination together, before traveling, and Chemitex were able to give me a next day appointment and a good price.
The service was excellent and friendly.
I thoroughly recommend.
No. Acetazolamide is a prescription-only medicine in the UK. You need a consultation first, and we can issue a private prescription the same day.
It’s best to avoid alcohol, especially for the first 48 hours at a new height. It can worsen dehydration, disturb sleep and hide early AMS symptoms.
No. It helps you adjust faster but doesn’t mask warning signs. If symptoms appear while taking it, stop climbing and rest until they settle.
Don’t go any higher. If symptoms worsen, or you notice confusion or breathlessness at rest, descend immediately and seek medical help.
Yes, paracetamol or ibuprofen can ease a mild altitude headache. Check with your pharmacist first if you have stomach, kidney or asthma problems.
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Chemitex Pharmacy is located at 332 Hornsey Road, London, N7 7HE. It’s just a short walk from Holloway Road and Finsbury Park stations. You’ll also find it near the Emirates Stadium. Book online using the link below, or call our team directly.
