acetazolamide at a glance
Medicine class
Carbonic anhydrase inhibitor
Licensed uses
Glaucoma, abnormal fluid retention and adjunctive treatment of some forms of epilepsy
Practical effects
Passing urine more often, tingling and taste changes can occur
What is acetazolamide used for?
Selected UK products are licensed for the following uses. Other established uses may be outside these licences.
Glaucoma, including open-angle and secondary glaucoma, and pressure reduction around acute angle-closure surgery.
Abnormal fluid retention, including fluid-retaining states where it may accompany other treatment.
Some forms of epilepsy, alongside other antiseizure treatment.
Outside the selected licences: idiopathic intracranial hypertension and acute mountain sickness.
How does acetazolamide work?
Acetazolamide blocks carbonic anhydrase. This increases kidney loss of bicarbonate, sodium, potassium and water, reduces fluid production and pressure in the eye, and can reduce cerebrospinal-fluid production.
acetazolamide preparations and strengths
Tablet
Route: Oral
Strengths: 250 mg
Injection
Route: Parenteral
Strengths: 500 mg
How to take acetazolamide
Follow the prescription label and discuss any treatment changes with the prescriber. Injection is reconstituted and administered by a healthcare professional.
Take tablets by mouth with water; taking them around a meal may help stomach upset.
The selected tablet has a score line and can be divided into equal parts when instructed.
Do not drive or operate machinery if drowsy, dizzy, confused or affected by temporary short-sightedness.
acetazolamide side effects
Common or expected effects
- Tingling or numbness, particularly in the fingers or toes
- Passing urine more often and increased thirst
- Nausea, vomiting, diarrhoea or reduced appetite
- Metallic or altered taste
- Headache, dizziness, tiredness or drowsiness
- Flushing, tinnitus or temporary short-sightedness
Get urgent medical advice
- Severe allergic reaction or sudden breathing difficulty
- Blistering, peeling or widespread pustular rash
- Sudden reduced vision or eye pain
- Fever, sore throat, unusual bruising or bleeding
- Jaundice, dark urine or pale stools
- Blood in the urine, severe flank pain or inability to pass urine
- Marked weakness, confusion or other symptoms of electrolyte imbalance
- New thoughts of self-harm
acetazolamide in pregnancy
Selected product information advises against acetazolamide during pregnancy, particularly in the first trimester, because human safety evidence is limited. Anyone pregnant, planning pregnancy or becoming pregnant should contact the prescriber promptly rather than independently stopping essential glaucoma or epilepsy treatment.
acetazolamide while breastfeeding
Acetazolamide has been detected at low levels in breast milk, but evidence is limited. Breastfeeding may be possible after individual prescriber or specialist assessment, with particular care for premature or unwell infants.
acetazolamide interactions
Check prescribed, over-the-counter and complementary products with a pharmacist or prescriber. Important interactions include:
Aspirin and other salicylates
Concurrent use can cause severe acidosis and increased nervous-system toxicity, particularly with substantial salicylate exposure.
Lithium
Acetazolamide increases lithium excretion and may reduce its blood concentration and effect.
Phenytoin, primidone and carbamazepine
Acetazolamide can alter their blood concentrations, requiring clinical review and monitoring.
Common questions about acetazolamide
Answers are fully visible for fast scanning and source review.
Is acetazolamide licensed for altitude sickness in the UK?
It is an established use but is outside the licences of the selected UK tablet and injection products.
Can acetazolamide affect driving?
Yes. Drowsiness, dizziness, confusion, poor coordination or temporary short-sightedness can impair driving; do not drive while affected.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.