Acetazolamide should be used with caution in:
- Patients with breathing problems, such as pulmonary obstruction and emphysema
- Patients with kidney problems, including a history of kidney stones
- Patients with high levels of calcium (hypercalcaemia)
- Patients who are dehydrated
- Patients with diabetes
It should not be used in:
- Patients with an allergy (hypersensitivity) to acetazolamide, or any of the other ingredients, or to sulfonamides
- Patients with low levels of potassium in the blood (hypokalaemia)
- Patients with low levels of sodium in the blood (hyponatraemia)
- Patients with severe kidney problems
- Patients with severe liver problems, including cirrhosis
- Patients with a problem with their metabolism called hyperchloremic acidosis
- Patients with adrenal gland problems, such as Addison's disease (a condition in which the adrenal glands do not make enough of certain hormones called cortisol and aldosterone, with symptoms such as weakness, dizziness and darkened patches of skin)
- Patients with an eye condition called chronic non-congestive angle-closure glaucoma (long-term use)
- Patients who are pregnant
Also see list of precautions and interactions.
Store below 25°C and keep in the original package or container.
What is it used for?
- Acetazolamide is used to treat abnormal fluid retention (oedema), increased pressure inside the eye (glaucoma) and epilepsy, a condition that is characterised by recurrent fits or convulsions.
- It is a type of carbonic anhydrase inhibitor.
- It is used to inhibit an enzyme called carbonic anhydrase, which is responsible for the production and breakdown of carbonic acid. Pressure in the eye is reduced by stopping carbonic anhydrase from working as this has the effect of reducing the amount of fluid in the eye. When used to treat abnormal fluid retention, acetazolamide causes more bicarbonate to be lost from the body. As bicarbonate takes water with it, an increased quantity of fluid is also lost from the body, reducing fluid retention. Acetazolamide is also thought to stabilise the activity of nerves, thereby helping to control fits and convulsions in epilepsy.
- In general this drug is used to reduce excess pressure in the eye (glaucoma) and abnormal fluid retention. It is also used with other drugs to control fits and convulsions in epilepsy.
Benefits of being on this drug can include:
- Reduction of raised pressure inside the eye owing to glaucoma, decrease in the number of fits and convulsions owing to epilepsy and a lessening of abnormal fluid retention (oedema).
Listed below are the typical uses of acetazolamide:
- Increased pressure inside the eye (glaucoma)
- Abnormal retention of fluids (oedema)
- Epilepsy (a condition with recurrent fits or convulsions).
On occasion your doctor may prescribe this medicine to treat a condition not on the above list. Such conditions are listed below.
- Mountain sickness, a condition that results from rapidly moving to high altitudes.
HOW TO USE/TAKE
How often do I take it?
- Take acetazolamide exactly as your doctor has told you. Tablets should be taken whole with a glass of water just before or after a meal. Do not chew or crush the tablets. Alternatively, a powdered form may be dissolved in water by a doctor or nurse, who will inject it into one of your veins or a muscle.
- Use this medication for the duration of the prescription in order to get the most benefit from it.
- Remember to use it at the same time each day - unless specifically told otherwise by your doctor.
- Certain medical conditions may require different dosage instructions as directed by your doctor.
- Dosage is based on your age, gender, medical condition, response to therapy, and use of certain interacting medicines.
Do I need to avoid anything?
- Acetazolamide may make you feel drowsy or confused, and may make you short-sighted (myopia). If this occurs, do not drive or operate machinery. Consult your doctor or pharmacist for more details.
When can I stop?
- Always complete the full course as prescribed by your doctor.
ACETAZOLAMIDE SIDE EFFECTS
- Feeling or being sick
- Loss of appetite
- A metallic taste in the mouth
- Passing more urine than normal
- Tiredness of irritability
- Feeling over-excited
- Tingling, numb or cold fingers or toes
- Drowsiness or confusion
- A loss of interest in sex (libido)
- Ringing in the ears or difficulty in hearing
- Short-sightedness, which usually gets better when the dosage is reduced or the drug stopped
This is not a complete list of possible side effects. If any of these persist or you consider them severe then inform doctor or pharmacist.
Tell your doctor immediately if you develop any of the following symptoms:
- Symptoms of high blood sugar, such as increased thirst or tiredness
- Unusual skin rashes
- Pain in the joints
- Lower-back pain
- Pain or a burning sensation when passing urine
- Difficulty passing urine
- Blood in your urine
- Stools that are pale in colour, or black and/or tarry
- Blood in stools
- Yellowing of the whites of the eyes or the skin
- Sore throat or fever
- Bruises that cannot be accounted for by injury
- Red or purple spots on the skin
- Weak muscles
- Having fits if these have not happened before
- Any thoughts about killing yourself.
Remember that your doctor has prescribed this medication because he or she has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.
A serious allergic reaction to this drug is unlikely, but seek immediate medical attention if it occurs. Symptoms of a serious allergic reaction include: rash, itching/swelling (especially of the face/tongue/throat), dizziness, trouble breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
The Yellow Card Scheme allows you to report suspected side effects from any type of medicine (which includes vaccines, herbals and over the counter medicines) that you are taking. It is run by the medicines safety watchdog called the Medicines and Healthcare products Regulatory agency (MHRA). Please report any suspected side effect on the Yellow Card Scheme website.
Before taking acetazolamide, tell your doctor or pharmacist if you are allergic to it; or to other sulfonamides; or if you have any other allergies.
This medication should not be used if you have certain medical conditions. Before using this medicine, consult your doctor or pharmacist in case of:
- Allergy (hypersensitivity) to acetazolamide, any of the other ingredients or sulphonamides
- Low levels of potassium in the blood (hypokalaemia)
- Low levels of sodium in the blood (hyponatraemia)
- Severe kidney problems
- Severe liver problems, including cirrhosis
- A problem with the metabolism called hyperchloremic acidosis
- Problems with the adrenal gland, such as Addison's disease (a condition in which the adrenal glands do not make enough of certain hormones called cortisol and aldosterone, with symptoms such as weakness, dizziness and darkened patches of skin)
- Long-term use in an eye condition called chronic non-congestive angle-closure glaucoma
Before using this medication, tell your doctor or pharmacist your medical history, especially any of the following:
- Breathing problems, such as pulmonary obstruction and emphysema
- Kidney problems, including a history of kidney stones
- High levels of calcium (hypercalcaemia)
Before having surgery, tell your doctor or dentist that you are taking this medication.
Does alcohol intake affect this drug?
- Alcohol does not affect this drug.
The elderly: acetazolamide should be used with caution in the elderly as they are more likely to have certain side effects.
Pregnancy and breast-feeding - please ensure you read the detailed information below
Acetazolamide is not safe to take if you are, or are planning to become, pregnant. Do not take acetazolamide, if you are pregnant or planning to become pregnant.
It is sensible to limit use of medication during pregnancy whenever possible. However, your doctor may decide that the benefits outweigh the risks in individual circumstances and after a careful assessment of your specific health situation.
If you have any doubts or concerns you are advised to discuss the medicine with your doctor or pharmacist.
Acetazolamide may be taken when breastfeeding but only on the advice of your doctor.
It is sensible to limit use of medication during breastfeeding whenever possible. However, your doctor may decide that the benefits outweigh the risks in individual circumstances and after a careful assessment of your specific health situation.
If you have any doubts or concerns you are advised to discuss the medicine with your doctor or pharmacist.
Before using this medicine, tell your prescriber of all the medicines you are taking including prescription medicines and medicines you have bought over the counter without a prescription. Tell your prescriber if you are taking vitamins or complementary remedies such as herbal products, as these can also interact with medicines.
If you are taking more than one medicine, these may interact with each other. Your prescriber may decide to use medicines which interact with each other if the benefit outweighs the risks. In these cases, the dose of your medicines may need to be adjusted or you may be monitored more closely.
The following medicines may interact with acetazolamide:
- Medicines for heart problems, such as digoxin
- Medicines to thin the blood and stop the formation of blood clots in the body, such as warfarin
- Medicines to reduce high blood pressure (hypertension)
- Medicines to treat diabetes
- Medicines for epilepsy or fits, such as phenytoin, primidone, carbamazepine and topiramate
- Medicines that interfere with folic acid, such as methotrexate, pyrimethamine and trimethoprim
- Corticosteroids that are used to treat a range of conditions, including skin diseases and joint pain or inflammation, such as prednisolone
- Aspirin and related drugs, such as salicylic acid or choline salicylate
- Other carbonic anhydrase inhibitors
- A medicine called ciclosporin that is used for various conditions, such as after organ transplant, or treating psoriasis (a skin condition) or rheumatoid arthritis
- Stimulants called amphetamines
- Quinidine, used to treat an irregular heartbeat
- Methenamine, used to prevent urine infections
- Lithium, used to treat depression
- Treatment with sodium bicarbonate.
This information does not contain all possible interactions. Therefore, tell your prescriber of all the products you are using before taking this medicine.
If you have a question or want to discuss anything about your medicine, speak to your local pharmacist.
If you take more acetazolamide tablets than you should, contact your doctor or go to the nearest hospital casualty department immediately.
If you think you, or someone you care for, might have accidentally taken more than the recommended dose of acetazolamide or intentional overdose is suspected, contact your local hospital, GP or if in England call 111. In Scotland call NHS 24. In Wales, call NHS Direct Wales. In the case of medical emergencies, always dial 999.
If you miss a dose, take it as soon as you remember. If it is within 2 hours of your next dose, skip the missed dose and resume your usual dosing schedule. Do not double the dose to catch up.