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Diamox is a medicine prescribed off-label to treat AMS, or altitude sickness. It works by helping the body to acclimatise to high altitude environments.

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Diamox SR250mg

Each Diamox SR tablet contains 250mg of acetazolamide. For altitude sickness, treatment may be one or two tablets a day for a specified number of days.

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Diamox is a medicine prescribed off-label to treat AMS, or altitude sickness. It works by helping the body to acclimatise to high altitude environments.

This content was reviewed by a clinician on

29 June 2021
dr daniel

Dr Daniel Atkinson

(GP Clinical Lead - GMC No. 4624794) 29 June 2021
Product information

Diamox SR is a medication made by Mercury Pharma, used to medicate a number of conditions. It is sometimes prescribed off-label for the treatment of altitude sickness, or AMS, an illness characterised by feelings of dizziness, exhaustion and headaches, and is induced by a lack of oxygen at high altitudes. Sometimes, this condition can lead to more serious symptoms, including loss of consciousness, and the coughing up of a white or pink foam.

  1. Effective at preventing sickness
  2. Sustained-release capsule
  3. Easy to swallow treatment

The higher a person climbs, the more severe symptoms are likely to be; however, it is more the rate at which one travels to these altitudes than the height which makes a difference. This is because the body needs to acclimatise to its new environment. Although it is rare, complications can result and prove fatal; so be aware that while treatment can help, it is recommended to get the advice of a climbing expert before embarking on your trip.

When someone encounters altitude sickness, their symptoms may be caused by: irregularities in the balance of fluid and electrolytes in the body; altered pH levels in the blood; and raised pressure in the lungs. The active ingredient in Diamox SR tablets is acetazolamide, and this works by increasing the secretion of alkali, or bicarbonate from the kidneys, into urine. This then raises the acidity level of the blood, spurring the body on to increase its circulation of oxygen; and helps it to become accustomed to its new surroundings.

Carefully follow the directions provided by your doctor when applying this treatment.

We do not provide Diamox through our online service. If you want to know more about this treatment and whether it is suitable for you, make an appointment with your GP. They will be able to give you specific guidance and issue a prescription where necessary.

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Page last reviewed:  29/06/2021


It is vital to read the safety information leaflet fully before using this product, and to adhere to the guidelines provided by your prescriber. Doing so will help you to get the most out of the medication and reduce the potential for side effects.

  1. Take as directed by your prescribing doctor.
  2. This may be one or two capsules a day, taken before food.
  3. Begin the treatment two days before ascent, so that you can become accustomed to any side effects it may cause.
  4. Swallow capsules whole and do not chew or crush them prior to use.
  5. Never take more than your doctor has told you to.
  6. If you miss a dose, do not compensate by taking a double dose. Ask your doctor for advice.

These directions are supplied as a guide only. Follow the instructions provided by your doctor during use.

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Page last reviewed:  29/06/2021
Please read the patient information leaflet for this medicine fully before use:

Diamox SR 250mg

Side effects & Warnings

Side effects

As with any medicine, it is important to be aware of the potential side effects this product may cause so that you can seek advice from your doctor in the event that they occur.

Visit your nearest doctor or hospital immediately if you experience any of the following: signs of an allergic reaction; a reduction in the number of white blood cells and ‘platelets’, resulting in unusual bruising or bleeding, fever, severe chills, sore throat or mouth ulcers; bruises or tiny red or purple spots on your skin; a severe condition of the skin that may affect the mouth and other parts of the body; weakness or paralysis, and reduced muscle tone; fits; pain or burning when you pass urine, have difficulty in passing urine, or have blood in your urine; stools which are black or tarry, or bloody; signs of liver disease such as jaundice; anaemia or bone marrow depression; pain in your lower back; or pale stools.

Other side effects include:

Headache, diarrhoea, feeling or being sick, loss of appetite, thirst, dizziness, loss of full control of arms or legs, flushing, increased urinary urgency, tiredness or irritability, feeling over-excited, a tingling or numbness in the fingers or toes, or coldness in the extremities, depression, drowsiness or confusion, loss of libido, tinnitus, or sight problems.

This is not a complete list of the side effects associated with this product. For a more detailed account, refer to the patient information leaflet supplied.

Taking it with other medications

Let your doctor know if you are currently using any other medications during consultation. These may be prescription, non-prescription or remedial products.

Diamox SR may interact with the following: medicines for your heart such as cardiac glycosides; treatments to reduce blood pressure; blood-thinners such as warfarin; anti-diabetic medications such as metformin; antiepileptics such as phenytoin, primidone or carbamazepine or topiramate; drugs which interfere with folic acid, such as methotrexate, pyrimethamine, or trimethoprim; steroids such as prednisolone; aspirin and related medicines; carbonic anhydrase inhibitors; amphetamines; quinidine; methenamine; lithium; sodium bicarbonate therapy; or ciclosporin.

Conditions to look out for

It is vital to tell your doctor if you have or have ever had any medical conditions which may affect your suitability to the medicine, including: kidney problems; lung problems; Addison’s disease; diabetes; or epilepsy.

Pregnancy and breastfeeding

Do not take Diamox if you are pregnant or breastfeeding, or trying to conceive.

Driving and using machinery

If you become dizzy or drowsy after taking Diamox, or have any sight problems, do not drive or use machines.

Page last reviewed:  29/06/2021
Please read the patient information leaflet for this medicine fully before use:

Diamox SR 250mg


Can I still drink alcohol?

Yes. Alcohol is not known to affect the way Diamox works. But it may be advisable not to drink alcohol if you are experiencing symptoms of altitude sickness (AMS), as this may make the condition worse.

Will I still be able to drive?

Yes. However, if you notice any side effects which may make driving dangerous, refrain from doing so and speak to a doctor.

Can I take this medicine while pregnant?

No. You must not use it if you are pregnant or suspect you might be, and talk to a consultant before use if you are breastfeeding.

How do I store it?

In a safe and secure environment at room temperature, below 30°C and out of the reach of children.

Am I allergic to anything in the medicine?

Each Diamox SR capsule contains 250mg acetazolamide, microcrystalline cellulose (E460), sodium lauryl sulphate, purified water, ethylcellulose, mineral oil, hydroxypropyl methylcellulose (E464), Pigment Blend PB-230005 Orange [hydroxypropyl cellulose, titanium dioxide and FD&C Yellow #6/Sunset yellow FCF aluminium lake (15-18% grade), Talc and FD&C Yellow #6/Sunset yellow FCF aluminium lake (38-42% grade)], gelatin, titanium dioxide (E171), yellow iron oxide (E172) and erythrosine (E127). Do not take them if you are allergic to any of these ingredients.

Is it available over-the-counter?

No. You can only buy Diamox with a prescription from a doctor. This is so that they can check whether it is appropriate for you to take.

Is it right for me?

We recommend that you speak to your GP in person if you want to find out whether Diamox is suitable for you. They will be able to give you specific advice and issue a prescription if suitable.


Page last reviewed:  29/06/2021 is rated 4.9 out of 5 by 3131 customers on TrustPilot!
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