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Know the basics|Know the precautions & warnings|Know the side effects|Know the interactions|Understand the dosage

Know the basics

What is acetazolamide used for?

Acetazolamide is used to prevent and reduce the symptoms of altitude sickness. This medication can decrease headache, tiredness, nausea, dizziness, and shortness of breath that can occur when you climb quickly to high altitudes (generally above 10,000 feet/3,048 meters). It is particularly useful in situations when you cannot make a slow ascent. The best ways to prevent altitude sickness are climbing slowly, stopping for 24 hours during the climb to allow the body to adjust to the new height, and taking it easy the first 1 to 2 days.

This drug is also used with other medications to treat a certain type of eye problem (open-angle glaucoma). Acetazolamide is a “water pill” (diuretic). It decreases the amount of fluid that can build up in the eye. It is also used to decrease a buildup of body fluids (edema) caused by congestive heart failure or certain medications. Acetazolamide can work less well over time, so it is usually used only for a short period.

It has also been used with other medications to treat certain types of seizures (petit mal and unlocalized seizures).

Acetazolamide may also be used to treat periodic paralysis.

How should I take acetazolamide?

If you are taking the tablets, take this medication by mouth, usually 1 to 4 times daily or as directed by your doctor. If you are taking the long-acting capsules, take this medication by mouth, usually 1 or 2 times daily or as directed by your doctor. Swallow the long-acting capsules whole. Do not open, break, or chew the capsules. Doing so can destroy the long action of the drug and may increase side effects.

Acetazolamide may be taken with or without food. Drink plenty of fluids unless otherwise directed by your doctor. Your dosage is based on your medical condition and response to therapy.

To prevent altitude sickness, start taking acetazolamide 1 to 2 days before you start to climb. Continue taking it while you are climbing and for at least 48 hours after you have reached your final altitude. You may need to continue taking this medication while staying at the high altitude to control your symptoms. If you develop severe altitude sickness, it is important that you climb down as quickly as possible. Acetazolamide will not protect you from the serious effects of severe altitude sickness. (See also Precautions.)

If you are taking this drug for another condition (e.g., glaucoma, seizures), use this medication regularly as directed to get the most benefit from it. To help you remember, take it at the same time(s) each day. Taking your last dose in the early evening will help prevent you from having to get up in the middle of the night to urinate. Consult your doctor or pharmacist if you have questions about your dosing schedule.

Do not increase or decrease your dose or stop using this medication without first consulting your doctor. Some conditions may become worse when this drug is suddenly stopped. Your dose may need to be gradually decreased.

When used for an extended period, this medication may not work as well and may require different dosing. Your doctor will be monitoring your condition. Tell your doctor if your condition does not improve or if it worsens (e.g., more frequent seizures).

This drug may reduce the potassium levels in your blood. Your doctor may recommend that you eat foods rich in potassium (e.g., bananas or orange juice) while you are taking this medication. Your doctor may also prescribe a potassium supplement for you to take during treatment. Consult your doctor for more information.

How do I store acetazolamide?

Acetazolamide is best stored at room temperature away from direct light and moisture. To prevent drug damage, you should not store acetazolamide in the bathroom or the freezer. There may be different brands of acetazolamide that may have different storage needs. It is important to always check the product package for instructions on storage, or ask your pharmacist. For safety, you should keep all medicines away from children and pets.

You should not flush acetazolamide down the toilet or pour them into a drain unless instructed to do so. It is important to properly discard this product when it is expired or no longer needed. Consult your pharmacist for more details about how to safely discard your product.

Know the precautions & warnings

What should I know before using acetazolamide?

Some medical conditions may interact with acetazolamide. Tell your doctor or pharmacist if you have any medical conditions, especially if any of the following apply to you:

  • If you are pregnant, planning to become pregnant, or are breast-feeding.
  • If you are taking any prescription or nonprescription medicine, herbal preparation, or dietary supplement.
  • If you have allergies to medicines, foods, or other substances.
  • If you have kidney stones, a lung disease, glaucoma (eg, chronic non-congestive angle-closure glaucoma), diabetes, or difficulty breathing.
  • If you have had a severe allergic reaction (eg, a severe rash, hives, breathing difficulties, or dizziness) to any other sulfonamide medicine such as acetazolamide, celecoxib, certain diuretics (eg, hydrochlorothiazide), glyburide, probenecid, sulfamethoxazole, valdecoxib, or zonisamide.

Some medicines may interact with acetazolamide. Tell your health care provider if you are taking any of the following medicines:

  • Salicylates (eg, aspirin) because they may increase the risk of acetazolamide’s side effects.
  • Other carbonic anhydrase inhibitors (eg, methazolamide), cyclosporine, quinidine, phenytoin, amphetamine, or sodium bicarbonate because the risk of their side effects may be increased by acetazolamide.
  • Primidone, salicylates (eg, aspirin), lithium, or methenamine because their effectiveness may be decreased by acetazolamide.

This may not be a complete list of all interactions that may occur. Ask your health care provider if acetazolamide may interact with other medicines that you take. Check with your health care provider before you start, stop, or change the dose of any medicine.

Is it safe to take acetazolamide during pregnancy or breast-feeding?

There are no adequate studies in women for determining risk when using this medication during pregnancy or while breastfeeding. Please always consult with your doctor to weigh the potential benefits and risks before taking this medication. This medication is pregnancy risk category C according to the US Food and Drug Administration (FDA).

FDA pregnancy risk category reference below:

  • A=No risk,
  • B=No risk in some studies,
  • C=There may be some risk,
  • D=Positive evidence of risk,
  • X=Contraindicated,
  • N=Unknown.

Know the side effects

What are the side effects of acetazolamide?

All medicines may cause side effects, but many people have no, or minor, side effects. Check with your doctor if any of these most common side effects persist or become bothersome:

  • Blurred vision;
  • Changes in taste;
  • Constipation;
  • Diarrhea;
  • Drowsiness;
  • Frequent urination;
  • Loss of appetite;
  • Nausea; vomiting.

Seek medical attention right away if any of these severe side effects occur:

  • Severe allergic reactions: rash; hives; difficulty breathing; tightness in the chest; swelling of the mouth, face, lips, or tongue;
  • Blood in urine;
  • Changes in hearing;
  • Convulsions;
  • Dark, bloody stools;
  • Dark urine;
  • Fast breathing;
  • Fever;
  • Lack of energy;
  • Lower back pain;
  • Red, swollen, or blistered skin;
  • Ringing in the ears;
  • Sore throat;
  • Tingling of the arms or legs;
  • Unusual bleeding or bruising;
  • Vision changes;
  • Yellowing of the skin or eyes.

Not everyone experiences these side effects. There may be some side effects not listed above. If you have any concerns about a side-effect, please consult your doctor or pharmacist.

Know the interactions

What drugs may interact with acetazolamide?

Acetazolamide may interact with other drugs that you are currently taking, which can change how your drug works or increase your risk for serious side effects. To avoid any potential drug interactions, you should keep a list of all the drugs you are using (including prescription drugs, non-prescription drugs and herbal products) and share it with your doctor and pharmacist. For your safety, do not start, stop, or change the dosage of any drugs without your doctor’s approval.

Although certain medicines should not be used together at all, in other cases two different medicines may be used together even if an interaction might occur. In these cases, your doctor may want to change the dose, or other precautions may be necessary. Tell your healthcare professional if you are taking any other prescription or non-prescription (over-the-counter [OTC]) medicine.

Using medicines in this class with any of the following medicines is not recommended. Your doctor may decide not to treat you with a medication in this class or change some of the other medicines you take.

Using medicines in this class with any of the following medicines is usually not recommended, but may be required in some cases. If both medicines are prescribed together, your doctor may change the dose or how often you use one or both of the medicines.

  • Aspirin, Arsenic Trioxide, Carbamazepine, Ceritinib, Dabrafenib, Digitalis, Droperidol, Eslicarbazepine Acetate, Idelalisib, Levomethadyl, Metformin, Mitotane, Nilotinib, Piperaquine, Proscillaridin, Quinidine, Siltuximab, Sotalol.

Does food or alcohol interact with acetazolamide?

Acetazolamide should be taken with food. Alcohol may interact with this drug and increase the risk of side effects. . Please discuss with your doctor or pharmacist any potential food or alcohol interactions before using this drug.

What health conditions may interact with acetazolamide?

Acetazolamide may interact with your health condition. This interaction may worsen your health condition or alter the way the drug works. It is important to always let your doctor and pharmacist know all the health conditions you currently have, especially:

  • Type 2 diabetes mellitus—Use of carbonic anhydrase inhibitors may increase the patient’s blood and urine sugar concentrations.
  • Emphysema or other chronic lung disease—Use of carbonic anhydrase inhibitors may increase the risk of acidosis (shortness of breath, troubled breathing).
  • Low blood levels of potassium or sodium—Use of carbonic anhydrase inhibitors may make the condition worse.
  • Kidney disease or stones—Higher blood levels of carbonic anhydrase inhibitors may result, which may increase the chance of side effects Also, these medicines may make the condition worse.
  • Liver disease—Use of carbonic anhydrase inhibitors may increase the risk of electrolyte imbalance and may make the condition worse.
  • Underactive adrenal gland (Addison’s disease)—Use of carbonic anhydrase inhibitors may increase the risk of electrolyte imbalance.

Understand the dosage

The information provided is not a substitute for medical advice. Always consult your doctor or pharmacist before using this medication.

What is the dose of acetazolamide for an adult?

Usual Adult Dose for Edema

  • 250 to 375 mg oral or intravenous once a day.

When continued acetazolamide therapy for edema is desired, it is recommended that every second or third dose be skipped to allow the kidney to recover.

Usual Adult Dose for Acute Mountain Sickness

  • Oral tablet: 125 to 250 mg orally every 6 to 12 hours.
  • SR capsule: 500 mg orally every 12 to 24 hours.

The maximum recommended dose is 1 gram/day.

For rapid ascent, higher doses are beneficial for preventing acute mountain sickness beginning 24 to 48 hours before ascent and continuing for 48 hours while at high altitude.

Usual Adult Dose for Glaucoma

Open-angle Glaucoma:

  • tablet or intravenous injection: 250 mg 1 to 4 times a day.
  • SR capsule: 500 mg once or twice a day.

Closed-angle glaucoma:

  • 250 to 500 mg intravenous, may repeat in 2 to 4 hours to a maximum of I gram/day.

Usual Adult Dose for Seizure Prophylaxis

  • 8 to 30 mg/kg/day in 1 to 4 divided doses. Do not exceed 1 gram per day.

If this patient is already taking other anticonvulsants, the recommended starting dosage is 250 mg once a day. If acetazolamide is used alone, most patients with good renal function respond to daily doses ranging from 375 to 1000 mg. The optimum dosage for this patient with renal dysfunction is not known, and will depend on this patient’s clinical response and tolerance.

Acetazolamide is primarily used for the treatment of refractory epilepsy in combination with other drugs. Although it may be useful in partial, myoclonic, absence, and primary generalized tonic-clonic seizures uncontrolled by other marketed agents, it has been inadequately studied by current standards for these conditions.

What is the dose of Acetazolamide for a child?

Usual Pediatric Dose for Glaucoma (over 1 year)

  • Oral: 8 to 30 mg/kg/day or 300 to 900 mg/m²/day divided every 8 hours.
  • intravenous: 20 to 40 mg/kg/day divided every 6 hours. Maximum dose: 1 gram/day.

Usual Pediatric Dose for Edema (over 1 year)

  • Oral or intravenous: 5 mg/kg or 150 mg/m² once a day.

Usual Pediatric Dose for Epilepsy (over 1 year)

  • Oral: 8 to 30 mg/kg/day in 1 to 4 divided doses. Maximum dose is 1 gram/day.

Usual Pediatric Dose for Hydrocephalus (under 1 year)

  • Oral or intravenous: 20 to 100 mg/kg/day divided every 6 to 8 hours. Maximum dose is 2 grams/day.

How is Acetazolamide available?

Acetazolamide is available in the following dosage forms and strengths:

Capsule Extended Release (ER) Oral: 500mg

Tablet, Oral: 125mg, 250mg

What should I do in case of an emergency or overdose?

In case of an emergency or an overdose, call your local emergency services or go to your nearest emergency room.

Symptoms of overdose may include:

  • Abnormal skin sensations (eg, tingling, tickling, itching, burning);
  • Buzzing, ringing, or whistling in the ears;
  • Drowsiness;
  • Loss of appetite;
  • Loss of coordination;
  • Nausea;
  • Tremors;
  • Unsteady movements;

What should I do if I miss a dose?

If you miss a dose of acetazolamide, take it as soon as possible. However, if it is almost time for your next dose, skip the missed dose and take your regular dose as scheduled. Do not take a double dose.

Hello Health Group does not provide medical advice, diagnosis or treatment.


Acetazolamide Pronunciation https://www.drugs.com/mtm/acetazolamide.html. Accessed July 6, 2016.

Acetazolamide (Diamox, Diamox Sequels) http://www.medicinenet.com/acetazolamide-oral/article.htm. Accessed July 6, 2016.
Acetazolamide Injection http://www.webmd.com/drugs/2/drug-5300/acetazolamide- injection/details. Accessed July 6, 2016.

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Written by Stephanie Nicole Nera, RPh, PharmD on May 02, 2020
Medically reviewed by Stephanie Nicole Nera, RPh, PharmD