3. Acetazolamide

Acetazolamide

  • You should not drive or operate machinery if you feel sleepy after taking this medicine.
  • Acetazolamide is not generally recommended for long-term use.
Type of medicine Carbonic anhydrase inhibitor
Used for Glaucoma
Some types of epilepsy
Fluid retention
Also called Diamox®
Diamox® SR
Available as Tablets, modified-release capsules and injection

Acetazolamide works by stopping the action of a chemical in the body called carbonic anhydrase. As a result, the amount of some salts in the body are reduced and this promotes a loss of fluid from the body.

Acetazolamide reduces the amount of fluid produced in the eye and this helps reduce the high pressure present in glaucoma.

Acetazolamide can also be useful in some types of epilepsy alongside other medicines.

Before taking acetazolamide make sure your doctor or pharmacist knows:

  • If you are pregnant, trying for a baby or breast-feeding.
  • If you have breathing problems.
  • If you know you have low potassium or sodium, or high levels of acid in your blood.
  • If you have liver or kidney problems, or trouble passing urine.
  • If you have a type of glaucoma called chronic non-congestive angle-closure glaucoma.
  • If you have diabetes mellitus.
  • If you have problems with your adrenal glands such as Addison's disease.
  • If you are taking other medicines, including those available to buy without a prescription, herbal and complementary medicines.
  • If you have ever had an allergic reaction to this or any other medicine. This is particularly important if you are allergic to sulphonamide antibiotics.
  • Before starting this treatment, read the manufacturer's printed information leaflet from inside the pack.
  • Take acetazolamide exactly as your doctor has told you. Your dose will depend on what you are being treated for.
  • If you have been given the modified-release capsules of acetazolamide (Diamox® SR), swallow these whole with a drink of water. They should not be chewed.
  • Try to take acetazolamide at the same time(s) each day to avoid missing any doses.
  • If you forget to take a dose, take it as soon as you remember unless it is nearly time for your next dose, in which case leave out the missed dose. Do not take two doses together to make up for a forgotten dose.
  • Keep your regular appointments with your doctor so your progress can be monitored.
  • Acetazolamide is not generally recommended for long-term use but if you need to take acetazolamide over a period of time your doctor will want you to have blood tests.
  • If you have diabetes, acetazolamide may affect your blood sugar levels. Test your urine or blood regularly and speak with your doctor if you notice any changes.
  • If you buy any medicines, check with a pharmacist that they are safe to take alongside acetazolamide.

Along with their useful effects, most medicines can cause unwanted side-effects although not everyone experiences them. These usually improve as your body adjusts to the new medicine, but speak with your doctor or pharmacist if any of the following side-effects continue or become troublesome.

Common side-effects - these affect less than 1 in 10 people who take this medicine What can I do if I experience this
Dizziness, drowsiness, tiredness Make sure your reactions are normal before driving, operating machinery or doing any other jobs which could be dangerous if you were not fully alert
Feeling or being sick Eat little and often. Stick to simple or bland foods. Taking the tablets at meal times may help
Diarrhoea Drink plenty of water to replace any lost fluids
Headache Ask your pharmacist to recommend a suitable painkiller
Changes in the way things taste, loss of appetite, flushing, mood changes, thirstiness, tingling feelings, increased need to pass urine, and reduced sexual desire If any of these become troublesome, speak with your doctor

Some medicines which can be used to treat epilepsy have been associated with a small risk of developing mood changes, distressing thoughts and feelings about suicide. The likelihood of having such thoughts with acetazolamide is not known, but if this happens to you, tell your doctor straight away.

If you experience any other symptoms which you think may be due to this medicine, speak with your doctor or pharmacist.

  • Keep all medicines out of the reach and sight of children.
  • Store in a cool, dry place, away from direct heat and light.

  • Never take more than the prescribed dose. If you suspect that you or someone else has taken an overdose of this medicine go to the accident and emergency department of your local hospital at once. Take the container with you, even if it is empty.
  • If you are having an operation or dental treatment, tell the person carrying out the treatment which medicines you are taking.
  • This medicine is for you. Never give it to other people even if their condition appears to be the same as yours.
  • Never keep out of date or unwanted medicines. Take them to your local pharmacy which will dispose of them for you.
  • If you have any questions about this medicine ask your pharmacist.
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Further reading & references

  • British National Formulary; 60th Edition (September 2010) British Medical Association and Royal Pharmaceutical Society of Great Britain, London.
  • Manufacturer's PIL, Diamox® Tablets 250 mg; Manufacturer's PIL, Diamox® Tablets 250 mg, Goldshield plc, electronic Medicines Compendium. Dated January 2006.
  • Manufacturer's PIL, Diamox® SR 250mg Capsules; Manufacturer's PIL, Diamox® SR 250mg Capsules, Goldshield plc, electronic Medicines Compendium. Dated September 2010.
Original Author: Helen Allen Current Version:
Last Checked: 20/04/2011 Document ID: 3257  Version: 24 © EMIS

Disclaimer: This article is for information only and should not be used for the diagnosis or treatment of medical conditions. EMIS has used all reasonable care in compiling the information but make no warranty as to its accuracy. Consult a doctor or other health care professional for diagnosis and treatment of medical conditions. For details see our conditions.