Acetazolamide
1 medicine
Acetazolamide is a carbonic anhydrase inhibitor used to lower eye pressure in glaucoma, prevent altitude sickness, and manage certain seizures and fluid retention. It is a sulfonamide medicine and must be avoided by anyone with a genuine sulfa-drug allergy.
Key facts
- Acetazolamide is a carbonic anhydrase inhibitor used to lower eye pressure in glaucoma, prevent altitude sickness, treat certain seizure disorders, and reduce fluid retention.
- You take it as tablets or extended-release capsules, with the dose and timing depending on the condition being treated.
- Acetazolamide is a sulfonamide. It must be avoided by anyone with a genuine sulfa-drug allergy, and it is avoided in severe liver disease, since it can trigger confusion or coma in that setting.
- It commonly causes tingling in the hands and feet and a metallic taste; report a severe rash, breathing difficulty, or confusion urgently.
What acetazolamide treats
Acetazolamide treats open-angle and some secondary glaucoma by lowering pressure inside the eye, prevents and treats acute mountain sickness at high altitude, controls certain types of epilepsy as an add-on treatment, and reduces fluid retention linked to some heart conditions. It is also used for metabolic alkalosis in hospital settings.
How acetazolamide works
Acetazolamide blocks carbonic anhydrase, an enzyme the kidneys and eye use to manage acid, bicarbonate, and fluid balance. In the kidney, blocking this enzyme causes more bicarbonate, sodium, and water to pass into the urine, which reduces fluid retention and helps the body adjust to low oxygen at altitude. In the eye, the same blockade reduces the fluid the eye produces, lowering pressure.
Before you take it
- Do not take acetazolamide if you have had a genuine allergic reaction to sulfonamide medicines, or if you have severe liver disease, severe kidney disease, or low sodium or potassium levels.
- Tell your doctor about adrenal gland problems, since acetazolamide can worsen adrenal insufficiency.
- Tell your prescriber about other diuretics, corticosteroids, and medicines that affect potassium, since combining them raises the risk of dangerously low potassium.
- Blood tests to check electrolytes and acid-base balance are usually needed before and during longer courses.
Side effects
Common effects include tingling or numbness in the hands or feet, frequent urination, mild dizziness, a metallic taste, and nausea.
Stop and seek urgent medical care for any of these:
- A spreading rash, blistering skin, or fever with sore throat, which can signal a severe drug reaction.
- Sudden swelling of the face, lips, tongue, or throat.
- Confusion, severe drowsiness, or yellowing of the skin or eyes.
Safety essentials
- Acetazolamide is a sulfonamide; anyone with a confirmed sulfa allergy must avoid it, and this is checked before the first dose.
- Regular blood tests for sodium, potassium, and acid-base balance are needed during treatment, since acetazolamide can cause metabolic acidosis and low potassium, especially combined with other diuretics.
- In severe liver disease, acetazolamide is avoided because it can trigger confusion or coma by disturbing how the body handles ammonia.
This page is educational and does not replace advice from a doctor or pharmacist who knows your health history.