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Acetazolamide

ACETAZOLAMIDE SODIUM

Standard Dose

DOSAGE AND ADMINISTRATION Preparation and Storage of Parenteral Solution Each 500 mg vial containing acetazolamide should be reconstituted with at least 5 mL of Sterile Water for Injection prior to use. Reconstituted solutions retain their physical and chemical properties for 3 days under refrigeration at 2° to 8°C (36° to 46°F), or 12 hours at room temperature 20° to 25°C (68° to 77°F). CONTAINS NO PRESERVATIVE. Discard unused portion. The direct intravenous route of administration is preferred. Intramuscular administration is not recommended. Glaucoma: Acetazolamide for Injection, USP should be used as an adjunct to the usual therapy. The dosage employed in the treatment of chronic simple (open-angle) glaucoma ranges from 250 mg to 1 gram of acetazolamide per 24 hours, usually in divided doses for amounts over 250 mg. It has usually been found that a dosage in excess of 1 gram per 24 hours does not produce an increased effect. In all cases, the dosage should be adjusted with careful individual attention both to symptomatology and ocular tension. Continuous supervision by a physician is advisable. In treatment of secondary glaucoma and in the preoperative treatment of some cases of acute congestive (closed-angle) glaucoma , the preferred dosage is 250 mg every four hours, although some cases have responded to 250 mg twice daily on short-term therapy. In some acute cases, it may be more satisfactory to administer an initial dose of 500 mg followed by 125 or 250 mg every four hours depending on the individual case. Intravenous therapy may be used for rapid relief of ocular tension in acute cases. A complementary effect has been noted when acetazolamide has been used in conjunction with miotics or mydriatics as the case demanded. Epilepsy: It is not clearly known whether the beneficial effects observed in epilepsy are due to direct inhibition of carbonic anhydrase in the central nervous system or whether they are due to the slight degree of acidosis produced by the divided dosage. The best results to date have been seen in petit mal in pediatric patients. Good results, however, have been seen in patients, both pediatric patients and adult, in other types of seizures such as grand mal, mixed seizure patterns, myoclonic jerk patterns, etc. The suggested total daily dose is 8 to 30 mg per kg in divided doses. Although some patients respond to a low dose, the optimum range appears to be from 375 to 1,000 mg daily. However, some investigators feel that daily doses in excess of 1 gram do not produce any better results than a 1 gram dose. When Acetazolamide for injection, USP is given in combination with other anticonvulsants, it is suggested that the starting dose should be 250 mg once daily in addition to the existing medications. This can be increased to levels as indicated above. The change from other medications to Acetazolamide for injection, USP should be gradual and in accordance with usual practice in epilepsy therapy. Congestive Heart Failure: For diuresis in congestive heart failure, the starting dose is usually 250 to 375 mg once daily in the morning (5 mg/kg). If, after an initial response, the patient fails to continue to lose edema fluid, do not increase the dose but allow for kidney recovery by skipping medication for a day. Acetazolamide for injection, USP yields best diuretic results when given on alternate days, or for two days alternating with a day of rest. Failures in therapy may be due to overdosage or too frequent dosage. The use of Acetazolamide for Injection, USP does not eliminate the need for other therapy such as digitalis, bed rest, and salt restriction. Drug-Induced Edema: Recommended dosage is 250 to 375 mg of Acetazolamide for injection, USP once a day for one or two days, alternating with a day of rest. Note: The dosage recommendations for glaucoma and epilepsy differ considerably from those for congestive heart failure, since the first two conditions are not dependent upon carbonic anhydrase inhibition in the kidney which requires intermittent dosage if it is to recover from the inhibitory effect of the therapeutic agent. Interference with Laboratory Tests Sulfonamides may give false negative or decreased values for urinary phenolsulfonphthalein and phenol red elimination values for urinary protein, serum non-protein and for serum uric acid. Acetazolamide for injection, USP may produce an increased level of crystals in the urine. Acetazolamide interferes with the HPLC method of assay for theophylline. Interference with the theophylline assay by acetazolamide depends on the solvent used in the extraction; acetazolamide may not interfere with other assay methods for theophylline.

Max Dose

See official label

Primary Use

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.

Summary

Dosage and administration DOSAGE AND ADMINISTRATION Preparation and Storage of Parenteral Solution Each 500 mg vial containing acetazolamide should be reconstituted with at least 5 mL of Sterile Water for Injection prior to use.

Structured Monograph

Clinical summary

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. Dosage and administration DOSAGE AND ADMINISTRATION Preparation and Storage of Parenteral Solution Each 500 mg vial containing acetazolamide should be reconstituted with at least 5 mL of Sterile Water for Injection prior to use. Reconstituted solutions retain their physical and chemical properties for 3 days under refrigeration at 2° to 8°C (36° to 46°F), or 12 hours at room temperature 20° to 25°C (68° to 77°F). CONTAINS NO PRESERVATIVE. Discard unused portion. The direct intravenous route of administration is preferred. Intramuscular administration is not recommended. Glaucoma: Acetazolamide for Injection, USP should be used as an adjunct to the usual therapy. The dosage employed in the treatment of chronic simple (open-angle) glaucoma ranges from 250 mg to 1 gram of acetazolamide per 24 hours, usually in divided doses for amounts over 250 mg. It has usually been found that a dosage in excess of 1 gram per 24 hours does not produce an increased effect. In all cases, the dosage should be adjusted with careful individual attention both to symptomatology and ocular tension. Continuous supervision by a physician is advisable. In treatment of secondary glaucoma and in the preoperative treatment of some cases of acute congestive (closed-angle) glaucoma , the preferred dosage is 250 mg every four hours, although some cases have responded to 250 mg twice daily on short-term therapy. In some acute cases, it may be more satisfactory to administer an initial dose of 500 mg followed by 125 or 250 mg every four hours depending on the individual case. Intravenous therapy may be used for rapid relief of ocular tension in acute cases. A complementary effect has been noted when acetazolamide has been used in conjunction with miotics or mydriatics as the case demanded. Epilepsy: It is not clearly known whether the beneficial effects observed in epilepsy are due to direct inhibition of carbonic anhydrase in the central nervous system or whether they are due to the slight degree of acidosis produced by the divided dosage. The best results to date have been seen in petit mal in pediatric patients. Good results, however, have been seen in patients, both pediatric patients and adult, in other types of seizures such as grand mal, mixed seizure patterns, myoclonic jerk patterns, etc. The suggested total daily dose is 8 to 30 mg per kg in divided doses. Although some patients respond to a low dose, the optimum range appears to be from 375 to 1,000 mg daily. However, some investigators feel that daily doses in excess of 1 gram do not produce any better results than a 1 gram dose. When Acetazolamide for injection, USP is given in combination with other anticonvulsants, it is suggested that the starting dose should be 250 mg once daily in addition to the existing medications. This can be increased to levels as indicated above. The change from other medications to Acetazolamide for injection, USP should be gradual and in accordance with usual practice in epilepsy therapy. Congestive Heart Failure: For diuresis in congestive heart failure, the starting dose is usually 250 to 375 mg once daily in the morning (5 mg/kg). If, after an initial response, the patient fails to continue to lose edema fluid, do not increase the dose but allow for kidney recovery by skipping medication for a day. Acetazolamide for injection, USP yields best diuretic results when given on alternate days, or for two days alternating with a day of rest. Failures in therapy may be due to overdosage or too frequent dosage. The use of Acetazolamide for Injection, USP does not eliminate the need for other therapy such as digitalis, bed rest, and salt restriction. Drug-Induced Edema: Recommended dosage is 250 to 375 mg of Acetazolamide for injection, USP once a day for one or two days, alternating with a day of rest. Note: The dosage recommendations for glaucoma and epilepsy differ considerably from those for congestive heart failure, since the first two conditions are not dependent upon carbonic anhydrase inhibition in the kidney which requires intermittent dosage if it is to recover from the inhibitory effect of the therapeutic agent. Interference with Laboratory Tests Sulfonamides may give false negative or decreased values for urinary phenolsulfonphthalein and phenol red elimination values for urinary protein, serum non-protein and for serum uric acid. Acetazolamide for injection, USP may produce an increased level of crystals in the urine. Acetazolamide interferes with the HPLC method of assay for theophylline. Interference with the theophylline assay by acetazolamide depends on the solvent used

Monitoring

• 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.

Interaction Notes

• 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.