acetazolamide
Acetazolamide is used to treat altitude sickness (mountain sickness). It can also help with glaucoma, edema (swelling), and epilepsy (a seizure condition). Acetazolamide can have side effects such as tiredness, stomach upset, and sometimes numbness and tingling of the face, arms, or legs. This medication comes as a generic immediate-release (IR) tablet and extended-release (ER) capsule; the brand-name Diamox is no longer available.
What is Acetazolamide?
What is Acetazolamide used for?
Altitude sickness (mountain sickness)
Glaucoma
Edema (swelling in the body due to fluid buildup) - IR tablet only
Epilepsy (petit mal, unlocalized seizures) - IR tablet only
How Acetazolamide works
Acetazolamide is a carbonic anhydrase inhibitor that affects your body's fluid and acid-base balance.
For altitude sickness, it allows your body to use oxygen better at high altitudes.
To help with edema in the body, acetazolamide removes extra water and electrolytes from your body and pass them into your urine. In addition, the medication lowers the amount of fluid in your eyes to treat glaucoma.
Though unclear, acetazolamide appears to calm your nervous system to help with seizures.
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What are the side effects of Acetazolamide?
Common Side Effects
- Tiredness
- Headache
- Nausea
- Vomiting
- Diarrhea
Other Side Effects
- Numbness or tingling of the face, arms, or legs
- Dizziness
- Drowsiness
- Blurred vision
- Loss of appetite
- Blurred vision
- Changes in taste
- Ringing in the ears (tinnitus)
- Urinating more often
Serious Side Effects
- Allergic reaction or severe skin reactions: hives, peeling or blistering skin, fever, trouble breathing, swelling of the face or lips
- Electrolyte or acid-base imbalance: nausea, muscle cramps, tiredness, weakness, rapid breathing, or confusion
Source: DailyMed
The following side effects have also been reported
Along with its needed effects, a medicine may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.
Check with your doctor immediately if any of the following side effects occur:
Rare
Shortness of breath or trouble in breathing
Check with your doctor as soon as possible if any of the following side effects occur:
More common
Unusual tiredness or weakness
Less common
Blood in urine
difficult urination
mental depression
pain in lower back
pain or burning while urinating
sudden decrease in amount of urine
Also, check with your doctor if you have any changes in your vision (especially problems with seeing faraway objects) when you first begin taking this medicine.
Some side effects may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
More common
general feeling of discomfort or illness
increase in frequency of urination or amount of urine (rare with methazolamide)
loss of appetite
metallic taste in mouth
nausea or vomiting
numbness, tingling, or burning in hands, fingers, feet, toes, mouth, lips, tongue, or anus
Less common or rare
dizziness or lightheadedness
drowsiness
feeling of choking or lump in the throat
headache
increased sensitivity of eyes to sunlight
loss of taste and smell
nervousness or irritability
Other side effects not listed may also occur in some patients. If you notice any other effects, check with your healthcare professional.
Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.
Pros and cons of Acetazolamide
Pros
Recommended preventative medication for altitude sickness if you're at moderate-to-high risk of developing this condition
Generally a well-tolerated medication
Can use in older people (at lower doses)
Available as a lower-cost generic
Cons
Need to take multiple times a day
Might not be a good option if you have a sulfonamide ("sulfa") allergy
Not recommended for people with serious kidney or liver problems
Not known if it's safe or works well in children (those of all ages for immediate-release and those younger than 12 for extended-release)
Pharmacist tips for Acetazolamide
For altitude sickness: It's preferred that you start acetazolamide 1 to 2 days before you ascend (climb up in altitude), such as before climbing a mountain or visiting a high-altitude location like Colorado. Continue to take the medication while at high altitudes for 2 days or longer if needed, and go up slowly to avoid getting sick.
Acetazolamide can cause drowsiness, tiredness, and changes in vision. Make sure you know how the medication affects you before you drive or do anything that requires concentration.
Acetazolamide might cause you to urinate more often. Your healthcare provider might recommend that you take the medication in the morning to avoid getting up at night.
Make sure to get any blood work done that your healthcare provider orders. Acetazolamide can cause changes to your electrolyte levels and, rarely, to your blood cell counts. For this reason, your provider might check your electrolyte levels and blood cell counts periodically while you're taking acetazolamide.
Don't take acetazolamide with aspirin unless your healthcare provider told you that it's okay to do so. Taking these two medications together can lead to side effects, such as loss of appetite, low energy, rapid breathing, or more seriously coma.
Let your healthcare provider and pharmacist know about all the medications you take or plan to take, including over-the-counter products and supplements. Acetazolamide can interact with other medications, such as antacids containing sodium bicarbonate; methotrexate; dorzolamide (Trusopt); and certain seizure medications like phenytoin (Dilantin) and primidone (Mysoline). These interactions can cause your medications to not work as well or raise your risk of certain side effects. Your providers can make sure acetazolamide is safe to take with your other medications.
Frequently asked questions about Acetazolamide
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What are the risks and warnings for Acetazolamide?
Acetazolamide can cause some serious health issues. This risk may be even higher for certain groups. If this worries you, talk to your doctor or pharmacist about other options.
Changes in acid-base balance and electrolyte levels
Risk factors: Kidney problems | Breathing problems | Diabetes | Age 65 years or older
Acetazolamide can cause electrolyte imbalances in your blood, including low sodium and potassium levels. It can also sometimes cause too much acid to build up in the body (metabolic acidosis). You might be at higher risk of these imbalances if you have kidney or breathing problems. Let your provider know if you experience nausea, muscle cramps, tiredness, weakness, rapid breathing, or confusion, as these can be signs of acid-base or electrolyte imbalances.
Changes in blood sugar levels
Acetazolamide can cause changes to your blood sugar levels. If you have diabetes, continue to check your blood sugar levels while you're taking acetazolamide. Let your provider know if your blood sugar levels are higher than usual. Also make sure you know how to recognize and treat low blood sugar, should it happen. Let your healthcare provider know if you experience symptoms of low blood sugar, such as shakiness, anxiety, or rapid heartbeat.
Interaction with aspirin
Risk factors: Taking acetazolamide with aspirin
Don't take high-dose aspirin with acetazolamide. These two medications interact with each other, possibly causing loss of appetite, breathing problems, tiredness, or even coma or death. Ask your healthcare provider before taking either acetazolamide or aspirin if you're already taking the other to make sure it's safe to do so.
Allergic reaction
Risk factors: Allergy to sulfa medications | Sensitive to FD&C Yellow No. 6 dye
It's possible to have an allergic reaction to acetazolamide. These reactions can be life-threatening and can include skin rashes, fever, blood problems, and anaphylaxis (closing of the throat). Acetazolamide is a sulfonamide medication; you might be at risk for allergic reactions to the medication if you have a sulfonamide (sulfa) allergy. In addition, some acetazolamide extended-release capsules contain FD&C Yellow No. 6 coloring dye, which some people might be sensitive to. If you have signs of an allergic reaction, like hives, blistered or peeling skin, trouble breathing, or swelling of your tongue or throat, stop using acetazolamide and get medical help right away.
Harm to unborn baby
It isn't known whether acetazolamide can harm an unborn baby when it's taken during pregnancy. But in animal studies, acetazolamide caused birth defects. Because of this risk, this medication should only be used during pregnancy if the benefits are greater than the potential risks. If you're pregnant or planning to become pregnant, discuss with your healthcare provider to see whether acetazolamide is safe for you to take.
Acetazolamide dosage forms
Typical dosing for Acetazolamide
Altitude sickness: The typical dose is 500 mg to 1,000 mg by mouth per day. This dose is usually separated into smaller doses throughout the day. It's recommended that you begin taking the medication 1 to 2 days before you go up in altitude.
Glaucoma: The typical dose ranges from 250 mg to 1,000 mg by mouth per day, separated into smaller doses throughout the day. The dose will depend on the type of glaucoma you have.
Edema: The typical dose ranges from 250 mg to 375 mg by mouth once a day. Sometimes, you might take acetazolamide every other day. The dose will depend on what's causing your edema.
Epilepsy: The typical dose ranges from 250 mg to 1,00 mg by mouth per day, separated into smaller doses throughout the day.
Altitude sickness: The typical dose is 500 mg to 1,000 mg by mouth per day, divided into smaller doses throughout the day. It's recommended that you begin taking the medication 1 to 2 days before you go up in altitude.
Glaucoma: The typical dose is 500 mg by mouth in the morning and evening.
Acetazolamide is also available as an intravenous (IV) injection that's administered by a healthcare provider.
Interactions between Acetazolamide and other drugs
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. When you are taking any of these medicines, it is especially important that your healthcare professional know if you are taking any of the medicines listed below. The following interactions have been selected on the basis of their potential significance and are not necessarily all-inclusive.
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.
- Aspirin
- Methenamine
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.
- Acyclovir
- Adefovir
- Amphetamine
- Arsenic Trioxide
- Benzphetamine
- Carbamazepine
- Ceritinib
- Dextroamphetamine
- Digitalis
- Droperidol
- Furosemide
- Levomethadyl
- Lisdexamfetamine
- Memantine
- Methamphetamine
- Methotrexate
- Porfimer
- Proscillaridin
- Quinidine
- Sotalol
- Valacyclovir
How much does Acetazolamide cost?
Acetazolamide contraindications
Low sodium levels (hyponatremia)
Low potassium levels (hypokalemia)
Severe kidney problems
Severe liver problems or liver cirrhosis
Adrenal gland failure
Hyperchloremic acidosis (a condition where there's too much acid in the body)
Long-term use in people with chronic angle-closure glaucoma
What are alternatives to Acetazolamide?
Altitude sickness (mountain sickness)
Glaucoma
Edema (swelling in the body due to fluid buildup) - IR tablet only
Epilepsy (petit mal, unlocalized seizures) - IR tablet only
What is the latest news about Acetazolamide?
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References
Best studies we foundAccord Healthcare Inc. (2023). ACETAZOLAMIDE capsule, extended release [package insert]. DailyMed.
Chartwell RX, LLC. (2023). ACETAZOLAMIDE tablet [package insert]. DailyMed.
Hackett, P., et al. (2023). High elevation travel & altitude illness. Centers for Disease Control and Prevention Yellow Book 2024.
Heidenreich, P. A., et al. (2022). 2022 AHA/ACC/HFSA guideline for the management of heart failure: A report of the American College of Cardiology/American Heart Association Joint Committee on Clinical Practice Guidelines. Circulation.
Heritage Pharmaceuticals Inc. d/b/a Avet Pharmaceuticals Inc. (2023). ACETAZOLAMIDE injection, powder, lyophilized, for solution [package insert]. DailyMed.
Lewis, J. L., III. (2023). Overview of acid-base balance. Merck Manual.
MedlinePlus. (2021). Metabolic acidosis.
Sharma, S., et al. (2023). Hyperchloremic acidosis. StatPearls.
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