Acetazolamide reduces the activity of a protein in your body called carbonic anhydrase. Blocking this protein can help reduce the build-up of certain fluids in the body.

Acetazolamide is used in people with certain types of glaucoma to reduce the amount of fluid in the eye, which decreases pressure inside the eye.

Acetazolamide is also used as a diuretic ("water pill") in people with congestive heart failure, to reduce the build-up of fluid in the body. This build-up is called edema.

Acetazolamide is also used to treat certain types of seizures, and to treat or prevent altitude sickness.

Acetazolamide may also be used for purposes not listed in this medication guide.

You should not use acetazolamide if you have cirrhosis, severe liver or kidney disease, an electrolyte imbalance, adrenal gland failure, or an allergy to acetazolamide or sulfa drugs.

Acetazolamide comes as a tablet and capsule to take by mouth. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take acetazolamide exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

If you are taking the extended-release (long-acting) form of acetazolamide (Diamox Sequels), do not crush or chew the capsules.

Follow all directions on your prescription label. Your doctor may occasionally change your dose to make sure you get the best results. Do not use acetazolamide in larger or smaller amounts or for longer than recommended.

Your dose of this medicine will depend on the condition you are treating. If you take acetazolamide for congestive heart failure, your doctor may tell you to skip your medication for a day. Follow your doctor's dosing instructions very carefully.

Take this medicine with a full glass of water.

While using acetazolamide, you may need frequent blood tests.

Acetazolamide may be only part of a complete treatment program that may also include other medications. Follow your doctor's instructions very closely.

Store at room temperature away from moisture and heat. Keep the bottle tightly closed when not in use.

You should not use acetazolamide if you are allergic to it, or if you have:

• severe liver disease, or cirrhosis;

• severe kidney disease;

• an electrolyte imbalance (such as acidosis or low levels of potassium or sodium in your blood);

• adrenal gland failure; or

• an allergy to sulfa drugs.

To make sure acetazolamide is safe for you, tell your doctor if you have:

• severe breathing problems;

• angle closure glaucoma; or

• if you also take aspirin in high doses.

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Acetazolamide can pass into breast milk and may harm a nursing baby. You should not breast-feed while using this medicine.

Acetazolamide is not approved for use by anyone younger than 18 years old.

Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

acetazolamide may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Avoid exposure to sunlight or tanning beds. Acetazolamide can make you sunburn more easily. Wear protective clothing and use sunscreen (SPF 30 or higher) when you are outdoors.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Acetazolamide may cause serious side effects. Call your doctor at once if you have:

• blood in urine or stools;

• a seizure (convulsions);

• loss of movement in any part of your body;

• a blood cell disorder--sudden weakness or ill feeling, fever, chills, sore throat, mouth sores, pale skin, feeling tired or short of breath, rapid heart rate, nosebleeds, bleeding gums;

• liver problems--nausea, upper stomach pain or swelling, tired feeling, loss of appetite, dark urine, clay-colored stools, jaundice (yellowing of the skin or eyes);

• signs of metabolic acidosis--confusion, vomiting, lack of energy, irregular heartbeats;

• signs of a kidney stone--pain in your side or lower back, blood in your urine, painful or difficult urination; or

• severe skin reaction--fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.

Common side effects of acetazolamide may include:

• nausea, vomiting, loss of appetite, diarrhea;

• numbness or tingling, especially in your arms and legs;

• drowsiness, confusion;

• hearing problems, ringing in your ears;

• increased urination; or

• altered sense of taste.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Other drugs may interact with acetazolamide, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Keep all appointments with your doctor and the laboratory. Your doctor will order certain tests to check your response to acetazolamide.

Do not let anyone else to take your medication. Ask your pharmacist any questions you have about refilling your prescription.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.