Acemox

Indications

Acetazolamide is used to lower raised pressure inside the eye in glaucoma (including short-term use before eye surgery), to prevent and treat altitude sickness, as an add-on treatment for some types of epilepsy, and occasionally to reduce fluid build-up (oedema) or raised pressure around the brain (idiopathic intracranial hypertension).

How It Works

Acetazolamide blocks an enzyme called carbonic anhydrase. In the eye this reduces the production of the fluid inside the eye, so eye pressure falls. In the kidneys it increases the loss of bicarbonate, sodium and water in the urine, which makes the blood slightly more acidic. This stimulates breathing and helps the body adjust to high altitude, and it may also calm abnormal electrical activity in the brain.

Dosage and Administration

• Glaucoma (adults): usually 250 mg one to four times daily, or as prescribed by the eye specialist.
• Prevention of altitude sickness (adults): commonly 125 mg twice daily, starting 1 day before the ascent and continuing for 2 days at the highest altitude, or as prescribed.
• Epilepsy, intracranial hypertension, oedema and children: as prescribed.

Take with food to reduce stomach upset and drink enough fluids. The injection form is given by a doctor or nurse.

Interactions

• High-dose Aspirin: can cause serious toxicity.
• Other diuretics and corticosteroids: increased risk of low potassium.
• Phenytoin, Carbamazepine and Primidone: blood levels and side effects may change.
• Lithium: levels may fall.
• Metformin: increased risk of lactic acidosis.
• Topiramate: increased risk of kidney stones and acidosis.

Contraindications

• Allergy to Acetazolamide or to sulfonamide (sulfa) medicines.
• Low blood sodium or potassium, or high blood chloride with acidosis.
• Severe kidney or liver disease, including cirrhosis.
• Adrenal gland failure (Addison's disease).
• Long-term use in angle-closure glaucoma (it is only used short term before surgery).

Side Effects

Common effects include tingling or pins and needles in the fingers, toes and around the mouth, passing more urine, altered taste (fizzy drinks may taste flat), loss of appetite, nausea, tiredness and drowsiness. Long-term use can cause kidney stones and low potassium. Rarely, it can cause serious skin reactions, blood disorders or liver problems.

Get urgent medical help if you develop a blistering or peeling rash, fever with sore throat or mouth ulcers, unusual bruising or bleeding, yellowing of the skin or eyes, severe back or side pain with blood in the urine, confusion, or fast deep breathing.

Pregnancy and Lactation

Avoid in pregnancy, especially the first three months, unless the doctor decides the benefit outweighs the risk. Small amounts pass into breast milk: use during breastfeeding only on a doctor's advice.

Precautions and Warnings

• Blood tests (blood count and salts) may be needed with long-term use.
• Use with care in elderly people, diabetes, gout, and lung conditions such as COPD.
• It may cause drowsiness: take care when driving.
• Altitude sickness: medicine does not replace slow ascent. If symptoms worsen, descend.

Overdose

Overdose may cause severe tingling, drowsiness, confusion, low potassium and acid build-up in the blood. Seek emergency medical help.

Therapeutic Class

Carbonic anhydrase inhibitor (anti-glaucoma agent, diuretic).

Storage

Store below 30°C in a dry place, away from light and out of the reach of children. Injections: as directed on the pack.