Medication Information Leaflet

What is this medication for?

Acetazolamide is usually used to control seizures (fits) and other problems related to the nervous system. It can also be used to help with altitude sickness prevention and treatment, to get rid of water retention (edema) and to relieve increased pressure in the eye. 

How should I take/use this medication?

Follow the instructions on your medication label and take the medication as prescribed by your doctor.

You can take this medication with or after food.

What should I do if I forget to take/use this medication?

If you miss a dose, take the missed dose as soon as you remember. If it is almost time for your next dose, take only the usual dose. Do not double your dose or use extra medication to make up for the missed dose. 

What precautions should I take?

Inform your healthcare professional if you have the following medical conditions before starting on Acetazolamide:
  • Sulfonamide allergy
  • Drug allergies
  • Kidney problems 
  • Liver problems
  • History of kidney stones

What are some common side-effects of this medication?

Like all medicines, this medication may cause some possible side effects but not everyone experiences them. Consult your healthcare professional if any of the side effects lasts more than a few days or become severe and bothersome.

The common side effects of Acetazolamide include:
  • Dizziness
    • Get up slowly from sitting or lying down position
  • Drowsiness
    • Avoid driving or engaging in activities (such as cycling or swimming) that requires concentration
  • Diarrhoea
    • Drink more water to replace loss of fluids
  • Nausea, vomiting
    • Take the medication with or after food to reduce nausea and vomiting
    • Avoid food that is too rich, spicy or has strong smells
  • Headache
    • Take paracetamol if needed to relieve headache
  • Loss of appetite, abdominal pain, taste disturbance (bitter taste)
  • Increase sensitivity to sunlight
    • Put on some sunscreen or wear long sleeves or pants to protect the skin
  • Irritability, feeling nervous and excitable
  • Muscle weakness, poor muscle coordination or numbness in the hands and feet (“pins and needles” sensation)

What are some rare but serious side-effects that I need to seek medical advice immediately?

The symptoms of a drug allergy include one or more of the following:
  • Swollen face /eyes/lips /tongue
  • Difficulty in breathing
  • Itchy skin rashes over your whole body
If you experience any of these symptoms, you should stop your medication and see your healthcare professional immediately.

If the following serious side effects happen, you should consult your healthcare professional immediately:
  • Blistering, peeling, red skin rash due to Stevens-Johnson syndrome (SJS) and Toxic Epidermal Necrolysis (TEN)
    • SJS and TEN are rare and serious skin reactions. Symptoms include face swelling, blisters on skin, skin rashes that spread within hours to days. It usually occurs within the first few months (monitor closely for the first 3 months) of treatment. 
    • As SJS and TEN progress rapidly, please consult your healthcare professional if you show the first sign of a rash.
  • Persistent blurred vision and/or eye pain, change in eyesight
  • Difficulty or pain when passing urine or blood in urine
  • Yellowing of the skin or eyes, or dark urine
  • Unusual bleeding or bruises
  • Prolonged fever, cough or mouth sores
  • Signs of too much acid in the blood: feeling confused, fast breathing, fast heartbeat, bad stomach pain, feeling very sleepy, shortness of breath or feeling very tired or weak

What food or medication should I avoid when I take this medication?

Avoid drinking alcohol while taking this medication as it can cause excessive drowsiness and dizziness.  

How should I store this medication?

Store in a cool and dry place, away from direct sunlight. Keep this medication away from children.

How should I throw away this medication safely?

Pack this medication into a black trash bag and seal it tightly before throwing it into the rubbish chute or bin.

If you take more than the recommended dose, please seek medical advice immediately. The information provided on this page does not replace information from your healthcare professional. Please consult your healthcare professional for more information.

This article is jointly developed by members of the National Medication Information workgroup. The workgroup consists of cluster partners (National Healthcare Group, National University Health System and SingHealth), community pharmacies (Guardian, Unity and Watsons) and Pharmaceutical Society of Singapore. The content does not reflect drug availability and supply information in pharmacies and healthcare institutions. You are advised to check with the respective institutions for such information.

Last updated on Aug 2021

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