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 or 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 or 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 when taking or using this medication?

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
  • Stand up or sit up slowly from a lying or sitting position.
• Drowsiness
  • This may affect your ability to drive and use machinery.
  • Make sure your reactions are normal before you drive or do things that require you to be alert.
• Loose stools (Diarrhoea)
  • Drink plenty of clear fluids to replace those lost (two liters every day).
  • Avoid oily or spicy food and milk or daily products.
  • You may have foods such as porridge or soups which are gentler on the stomach.
  • Take the anti-diarrheal medication (e.g., Loperamide) that the doctor gives you when necessary.
• Nausea, vomiting
  • Take the medication after food, eat small but frequent meals.
  • Avoid fatty or spicy food.
• Headache
  • You may take paracetamol to treat the headache.
• Loss of appetite, abdominal pain, taste disturbance (bitter taste)
• Increase sensitivity to sunlight (photosensitivity)
  • This medication may make you more sensitive to the sun.
  • Hence, avoid prolonged sun exposure, tanning booths, and sunlamps.
  • Use sunscreen and wear protective clothing when outdoors.
• 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 which can happen after using some medications.
• Symptoms include mouth ulcers, face swelling, blisters on skin, skin rashes that spread throughout the body within hours to days after starting the medication.
• This usually occurs within the first few months (monitor closely for the first 3 months) of treatment.
• 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 or use 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 do 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.

Disclaimer

Please take note that the above is not a complete list of all possible side effects. If you have any concerns about your medication or if you have other side effects that you think are caused by this medication, please consult your doctor or pharmacist.

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 Jan 2025