Neptazane reduces the activity of a protein in your body called carbonic anhydrase. Blocking this protein can help reduce the amount of fluid in the eye, which decreases pressure inside the eye.

Neptazane is used to lower pressure inside the eye (intraocular pressure) in people with certain types of glaucoma.

Neptazane 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.

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

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

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

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 Neptazane in larger or smaller amounts or for longer than recommended.

While using Neptazane, you may need frequent blood tests.

Neptazane 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 Neptazane 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 Neptazane 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.

It is not known whether methazolamide passes into breast milk or if it could harm a nursing baby. You should not breast-feed while using this medicine.

Neptazane 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.

Neptazane 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. Neptazane 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.

Neptazane 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 Neptazane 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.

Tell your doctor about all your current medicines and any you start or stop using, especially:

• steroid medicine (prednisone, dexamethasone, and others).

This list is not complete. Other drugs may interact with methazolamide, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.