Acetazolamide Extended-Release

Description

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: Molecular Weight 222.24 Chemical Formula C 4 H 6 N 4 O 3 S 2 Acetazolamide extended-release capsules, USP are, for oral administration, each containing 500 mg of acetazolamide and the following inactive ingredients: hydroxypropyl cellulose, microcrystalline cellulose, sodium lauryl sulfate and talc. The ingredients in the capsule shell are D&C RED no. 28, D&C YELLOW no. 10, FD&C RED no. 40, gelatin and titanium dioxide. The ingredients in the imprinting ink are shellac (24 to 27%), dehydrated alcohol (23 to 26%), isopropyl alcohol (1 to 3%), butyl alcohol (1 to 3%), propylene glycol (3 to 7%), strong ammonia solution (1 to 2%), black iron oxide (24 to 28%), potassium hydroxide (0.05 to 0.1%) and purified water (15 to 18%). FDA approved dissolution test specifications differ from USP acetazolamide-str.jpg

What Is Acetazolamide Extended-Release Used For?

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

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, USP 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.

Side Effects (Adverse Reactions)

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. To report SUSPECTED ADVERSE REACTIONS, contact Micro Labs USA Inc., at 1-855-839-8195 or the FDA at 1-800-FDA-1088 or www.fda.gov/medwatch .

Drug Interactions

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.

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 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.

Pregnancy and Breastfeeding

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.

Nursing Mothers Because of the potential for serious adverse reactions in nursing infants from acetazolamide, a decision should be made whether to discontinue nursing or to discontinue the drug taking into account the importance of the drug to the mother. Acetazolamide should only be used by nursing women if the potential benefit justifies the potential risk to the child.

Overdosage

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

HOW SUPPLIED: Acetazolamide Extended-Release Capsules, USP are available as 500 mg: Opaque orange / Opaque orange, hard gelatin capsule imprinted with 'M' on cap and '26' on body contains white to off white pellets. Available in bottles of: Bottles of 100 NDC 42571-243-01 Store at 20° to 25°C(68° to 77°F) [see USP Controlled Room Temperature]. Dispense in well-closed containers. Manufactured by: Micro Labs Limited INDIA. Manufactured for: Micro Labs USA Inc. Somerset, NJ 08873 Rev. 12/2025