What it is used for
- Lowering pressure in glaucoma or before selected eye procedures
- Add-on treatment for selected epilepsies under a neurologist's plan
- Treating fluid retention in selected conditions when prescribed
- Preventing or treating early altitude illness alongside safe-ascent measures
How it is used
- Take tablets only as prescribed and swallow them with water; do not alter the dose or stop glaucoma or epilepsy treatment yourself
- It may be taken with food if it upsets the stomach, and follow the doctor's advice about fluids and diet
- Injection powder is prepared and given into a vein by a hospital professional when urgent treatment is needed or oral treatment is unsuitable
- For altitude illness, follow the doctor's plan and ascend gradually; the medicine does not make further ascent safe when severe symptoms develop
Possible side effects
- Tingling or numbness in the fingers or face
- Increased urination, thirst, tiredness or dizziness
- Nausea, diarrhoea, altered taste or reduced appetite
- Electrolyte imbalance or increased blood acidity
- Kidney stones or, rarely, a skin rash
Who should not use it
- Severe kidney or liver disease, cirrhosis, or adrenal-gland failure
- Low blood sodium or potassium, or hyperchloraemic acidosis
- Allergy to acetazolamide or a previous serious reaction to a sulfonamide medicine
- Long-term use in a particular form of chronic non-congestive angle-closure glaucoma
Before and while using it
- Electrolytes, kidney function and blood counts may need monitoring; report marked weakness, an abnormal heartbeat or confusion
- Stop the medicine and seek urgent assessment for a widespread rash, blisters, mouth sores, fever or unusual bruising
- Sudden eye pain, short-sightedness or reduced vision may indicate choroidal swelling or detachment and needs urgent assessment
- It can increase kidney-stone risk; tell the doctor about previous stones, flank pain or blood in urine
- Watch for mood change or thoughts of self-harm and seek help immediately if they occur
- Severe altitude illness with breathlessness at rest, loss of coordination or confusion requires descent and emergency help, not reliance on the medicine
Medicine interactions
- High-dose aspirin can cause serious toxicity and acidosis when combined with it
- Sodium bicarbonate increases kidney-stone risk, and combining it with another carbonic anhydrase inhibitor is not recommended
- It can alter the effect or level of phenytoin, carbamazepine, primidone, lithium and ciclosporin
- The effects of anticoagulants, diabetes medicines, digoxin and some blood-pressure medicines may change; tell the doctor about all your medicines
Pregnancy and breastfeeding
- Tell the doctor if you are pregnant or planning pregnancy; it is used only after specialist assessment of benefit and risk
- It enters milk in limited amounts; the doctor decides whether breastfeeding is suitable for you and the infant
How to store it
- Keep tablets in the original pack away from moisture, heat and children's reach; hospital staff store and prepare injection powder according to product instructions
Get medical help straight away if
- Your face, lips or tongue swell, or you find it hard to breathe.
- You get a severe rash, blistering or peeling skin.
- A side effect worries you or doesn’t go away: contact your doctor or pharmacist.
Questions about this medicine?
Talk to a doctor by video, or send your question by text.
Source: Standard international medicine references
This guide is general information and doesn’t replace advice from your doctor or pharmacist. Don’t start, stop or change a medicine without asking them, and always read the leaflet in the pack.