acetazolamide

INDICATIONS AND USAGE: For adjunctive treatment of: 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 extended-release capsules are also indicated for the prevention or amelioration of symptoms associated with acute mountain sickness despite gradual ascent.

DOSAGE AND ADMINISTRATION: Glaucoma The recommended dosage is 1 capsule (500 mg) two times a day. Usually 1 capsule is administered in the morning and 1 capsule in the evening. It may be necessary to adjust the dose, but it has usually been found that dosage in excess of 2 capsules (1 g) does not produce an increased effect. The dosage should be adjusted with careful individual attention both to symptomatology and intraocular tension. In all cases, continuous supervision by a physician is advisable. In those unusual instances where adequate control is not obtained by the twice-a-day administration of acetazolamide extended-release capsules, the desired control may be established by means of acetazolamide (tablets or parenteral). Use tablets or parenteral in accordance with the more frequent dosage schedules recommended for these dosage forms, such as 250 mg every four hours, or an initial dose of 500 mg followed by 250 mg or 125 mg every four hours, depending on the case in question. Acute Mountain Sickness Dosage is 500 mg to 1000 mg daily, in divided doses using tablets or extended-release capsules as appropriate. In circumstances of rapid ascent, such as in rescue or military operations, the higher dose level of 1000 mg is recommended. It is preferable to initiate dosing 24 to 48 hours before ascent and to continue for 48 hours while at high altitude, or longer as necessary to control symptoms.

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 non-congestive angle-closure glaucoma since it may permit organic closure of the angle to occur while the worsening glaucoma is masked by lowered intraocular pressure.

ADVERSE REACTIONS: Body as a whole: Headache, malaise, fatigue, fever, pain at injection site, 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, 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, paresthesia (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.

Drug Interactions Aspirin - See WARNINGS Acetazolamide modifies phenytoin metabolism with increased serum levels of phenytoin. This may increase or enhance the occurrence of osteomalacia in some patients receiving chronic phenytoin therapy. Caution is advised in patients receiving chronic concomitant therapy. By decreasing the gastrointestinal absorption of primidone, acetazolamide may decrease serum concentrations of primidone and its metabolites, with a consequent possible decrease in anticonvulsant effect. Caution is advised when beginning, discontinuing, or changing the dose of acetazolamide in patients receiving primidone. Because of possible additive effects with other carbonic anhydrase inhibitors, concomitant use is not advisable. Acetazolamide may increase the effects of other folic acid antagonists. Acetazolamide decreases urinary excretion of amphetamine and may enhance the magnitude and duration of their effect. Acetazolamide reduces urinary excretion of quinidine and may enhance its effect. Acetazolamide may prevent the urinary antiseptic effect of methenamine. Acetazolamide increases lithium excretion and the lithium may be decreased. Acetazolamide and sodium bicarbonate used concurrently increase the risk of renal calculus formation. Acetazolamide may elevate cyclosporine levels.

DESCRIPTION: Acetazolamide Extended-release Capsules, USP are an inhibitor of the enzyme carbonic anhydrase. Acetazolamide, USP is a white to faintly yellowish white, crystalline odorless powder, sparingly soluble in practically boiling water, slightly soluble in alcohol, very slightly soluble in water. The chemical name for acetazolamide is N-(5-Sulfamoyl-1,3,4-thiadiazol-2-yl) acetamide and has the following chemical structure: MW 222.25 C 4 H 6 N 4 O 3 S 2 Each acetazolamide extended-release capsule, USP intended for oral administration contains 500 mg of acetazolamide. In addition, each capsule contains the following inactive ingredients: gelatin, iron oxide yellow, microcrystalline cellulose, sodium lauryl sulfate, talc and titanium dioxide. Each capsule is printed with black pharmaceutical ink which contains black iron oxide, butyl alcohol, dehydrated alcohol, isopropyl alcohol, potassium hydroxide, propylene glycol, shellac and strong ammonia solution. Meets USP Dissolution Test 3. figure

OVERDOSAGE: No specific antidote is known. Treatment should be symptomatic and supportive. Electrolyte imbalance, development of an acidotic state, and central nervous system 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 may be dialyzable. This may be particularly important in the management of acetazolamide overdosage when complicated by the presence of renal failure.

HOW SUPPLIED: Acetazolamide Extended-release Capsules USP, 500 mg are white to off white pellets filled in size "00el" empty hard gelatin capsules with opaque yellow colored cap imprinted with "XYL" in black ink and opaque white colored body imprinted with "34" in black ink and are supplied as follows: NDC 70710-1591-3 in bottles of 30 capsules with child-resistant closure NDC 70710-1591-9 in bottles of 90 capsules with child-resistant closure NDC 70710-1591-1 in bottles of 100 capsules with child-resistant closure NDC 70710-1591-5 in bottles of 500 capsules NDC 70710-1591-0 in bottles of 1000 capsules NDC 70710-1591-4 in unit-dose blister cartons of 100 (10 x 10) unit-dose capsules Storage Store at 20° to 25°C (68° to 77°F) [See USP Controlled Room Temperature] . Dispense in a tight container (USP). Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088. Manufactured by: Zydus Lifesciences Ltd. Ahmedabad, India Distributed by: Zydus Pharmaceuticals (USA) Inc. Pennington, NJ 08534 Rev.: 10/24