FDA-approved label information
Reproduced from the FDA Structured Product Label via the openFDA API. Label version: May 12, 2026.
- Status
- Human Prescription Drug
- Brand names
- acetazolamide
- Route
- Oral
- Drug class
- Carbonic Anhydrase Inhibitor [EPC]
Description
DESCRIPTION Acetazolamide, an inhibitor of the enzyme carbonic anhydrase is a white to faintly yellowish white crystalline, odorless powder, weakly acidic, very slightly soluble in water and slightly soluble in alcohol. The chemical name for acetazolamide is N -(5-Sulfamoyl-1,3,4-thiadiazol-2-yl) acetamide and has the following chemical structure: Molecular Weight: 222.24 Molecular Formula: C 4 H 6 N 4 O 3 S 2 Acetazolamide tablets, USP are available for oral administration each containing 125 mg and 250 mg of acetazolamide respectively. Additionally, they contain the following inactive ingredients: lactose monohydrate, magnesium stearate, microcrystalline cellulose, povidone, pregelatinized starch, sodium lauryl sulfate, and sodium starch glycolate. structure
Indications and usage
INDICATIONS AND USAGE For adjunctive treatment of: edema due to congestive heart failure; drug-induced edema; centrencephalic epilepsies (petit mal, unlocalized seizures); chronic simple (open-angle) glaucoma, secondary glaucoma, and preoperatively in acute angle-closure glaucoma where delay of surgery is desired in order to lower intraocular pressure. Acetazolamide tablets are also indicated for the prevention or amelioration of symptoms associated with acute mountain sickness in climbers attempting rapid ascent and in those who are very susceptible to acute mountain sickness despite gradual ascent.
Contraindications
CONTRAINDICATIONS Hypersensitivity to acetazolamide or any excipients in the formulation. Since acetazolamide is a sulfonamide derivative, cross sensitivity between acetazolamide, sulfonamides and other sulfonamide derivatives is possible. Acetazolamide therapy is contraindicated in situations in which sodium and/or potassium blood serum levels are depressed, in cases of marked kidney and liver disease or dysfunction, in suprarenal gland failure, and in hyperchloremic acidosis. It is contraindicated in patients with cirrhosis because of the risk of development of hepatic encephalopathy. Long-term administration of acetazolamide is contraindicated in patients with chronic noncongestive angle-closure glaucoma since it may permit organic closure of the angle to occur while the worsening glaucoma is masked by lowered intraocular pressure.
Warnings (older label format)
WARNINGS Fatalities have occurred, although rarely, due to severe reactions to sulfonamides including Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia, and other blood dyscrasias, and anaphylaxis. Sensitizations may recur when a sulfonamide is readministered irrespective of the route of administration. If signs of hypersensitivity or other serious reactions occur, discontinue use of this drug. Caution is advised for patients receiving concomitant high-dose aspirin and acetazolamide, as anorexia, tachypnea, lethargy, metabolic acidosis, coma, and death have been reported.
Adverse reactions
ADVERSE REACTIONS Body as a whole: Headache, malaise, fatigue, fever, flushing, growth retardation in children, flaccid paralysis, anaphylaxis Digestive: Gastrointestinal disturbances such as nausea, vomiting, diarrhea Hematological/Lymphatic: Blood dyscrasias such as aplastic anemia, agranulocytosis, leukopenia, thrombocytopenia, thrombocytopenic purpura, melena Hepato-biliary disorders: Abnormal liver function, cholestatic jaundice, hepatic insufficiency, fulminant hepatic necrosis Metabolic/Nutritional: Metabolic acidosis, electrolyte imbalance, including hypokalemia, hyponatremia, osteomalacia with long-term phenytoin therapy, loss of appetite, taste alteration, hyper/hypoglycemia Nervous: Drowsiness, paraesthesia (including numbness and tingling of extremities and face), depression, excitement, ataxia, confusion, convulsions, dizziness Skin: Allergic skin reactions including urticaria, photosensitivity, Stevens-Johnson syndrome, toxic epidermal necrolysis Otologic : Hearing disturbances, tinnitus Eye Disorders: choroidal effusion, choroidal detachment, transient myopia. Transient myopia is the result of forward movement of the ciliary body leading to a narrowing of the angle. Urogenital: Crystalluria, increased risk of nephrolithiasis with long-term therapy, hematuria, glycosuria, renal failure, polyuria Postmarketing Experience: The following adverse reactions have been identified during post approval use of acetazolamide. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Respiratory, thoracic and mediastinal disorders: Non-cardiogenic pulmonary edema has been reported following cataract surgery. To report SUSPECTED ADVERSE REACTIONS, contact Avet Pharmaceuticals Inc. at 1-866-901-DRUG (3784) or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.
Pregnancy
Pregnancy: Teratogenic effects Acetazolamide, administered orally or parenterally, has been shown to be teratogenic (defects of the limbs) in mice, rats, hamsters, and rabbits. There are no adequate and well-controlled studies in pregnant women. Acetazolamide should be used in pregnancy only if the potential benefit justifies the potential risk to the fetus.
Paediatric use
Pediatric Use The safety and effectiveness of acetazolamide in pediatric patients have not been established. Growth retardation has been reported in children receiving long-term therapy, believed secondary to chronic acidosis.
Overdosage
OVERDOSAGE No specific antidote is known. Treatment should be symptomatic and supportive. Electrolyte imbalance, development of an acidotic state, and central nervous effects might be expected to occur. Serum electrolyte levels (particularly potassium) and blood pH levels should be monitored. Supportive measures are required to restore electrolyte and pH balance. The acidotic state can usually be corrected by the administration of bicarbonate. Despite its high intraerythrocytic distribution and plasma protein binding properties, acetazolamide is dialyzable. This may be particularly important in the management of acetazolamide overdosage when complicated by the presence of renal failure.
Source: US Food and Drug Administration, via the openFDA API. The FDA does not review, endorse or verify third-party reproductions of this data, and label information may have been updated since it was retrieved.
Read the current full label on DailyMed
FDA approval applies to the uses listed on the label. Approval status in your country may differ.
