Acetazolamide Sodium

Name: Acetazolamide Sodium

Introduction

Carbonic anhydrase inhibitor; nonbacteriostatic sulfonamide derivative.a b c d e

Uses for Acetazolamide Sodium

Glaucoma

Adjunctive treatment of open-angle or secondary glaucoma.c d e

Short-term use in acute angle-closure glaucoma to lower intraocular pressure (IOP) before surgery.a b c d e Should not be used for long-term treatment of angle-closure glaucoma.b c d e (See Contraindications under Cautions.)

Acute Mountain Sickness

Prevention or amelioration of symptoms (e.g., headache, lassitude, insomnia, nausea, shortness of breath, dizziness) associated with acute mountain sickness.a b c d f

Shortens the time of acclimatization.f If acute mountain sickness develops, shortens duration; does notobviate need to stop ascent or to descend.f

Also used in the treatment and prevention of high-altitude sleep disorders.c d f Decreases periodic breathing and apnea and improves oxygenation.f

Seizure Disorders

Management (in combination with other anticonvulsants) of centrencephalic epilepsies (e.g., petit mal, unlocalized seizures);c e may be ineffective for prolonged therapy.a b Has not been evaluated in controlled clinical studies in specific seizure types.a b

Edema

Adjunctive treatment of edema due to CHF or drug therapy.b c e Less potent diuretic than thiazide diuretics; metabolic acidosis resulting in loss of diuretic effect occurs after 2–4 days of continuous therapy.b

Periodic Paralysis

Has been used in the treatment of hyperkalemic and hypokalemic forms of periodic paralysis†.404 405 407 409 412 413

Acetazolamide Sodium Dosage and Administration

Administration

Administer orally or by direct IV injection.c d e

Do not administer IM; injection is painful.b e

Oral Administration

When an oral liquid preparation is needed, crush the appropriate number of tablets and suspend in a highly flavored carbohydrate syrup.a Can suspend up to 500 mg of acetazolamide in 5 mL of syrup; suspensions containing 250 mg per 5 mL are more palatable.a Alternatively, soften a tablet in 2 teaspoonsful of hot water and add 2 teaspoonsful of honey or syrup; swallow immediately.a

When the extended-release capsules are used for glaucoma, if adequate response is not achieved with twice-daily administration of this preparation, consider using other acetazolamide preparations that are administered more frequently (i.e., tablet, parenteral preparation) to achieve IOP control.d

IV Administration

For solution and drug compatibility information, see Compatibility under Stability.

Administer IV when rapid lowering of IOP is necessary or if patient is unable to take oral medication.a e

Reconstitution

Reconstitute vial containing 500 mg of acetazolamide with 5 mL of sterile water for injection to provide a solution containing 100 mg/mL.a e

Dosage

Available as acetazolamide (oral preparations) and acetazolamide sodium; dosage expressed in terms of acetazolamide.c d e

Adjust dosage based on patient response and requirements.a

Pediatric Patients

Glaucoma Oral

8–30 mg/kg or 300–900 mg/m2 daily in 3 divided doses has been used.a

Open-angle or Secondary Glaucoma Oral

Children ≥12 years of age: 500 mg twice daily as extended-release capsules.d

Acute Angle-closure Glaucoma Oral

Children ≥12 years of age: 500 mg twice daily as extended-release capsules.d

IV

5–10 mg/kg every 6 hours has been used.a

Acute Mountain Sickness Oral

Children ≥12 years of age: 500 mg once or twice daily as extended-release capsules.d Initiate 24–48 hours before ascent; continue for 48 hours while at high altitude or longer if needed to control symptoms.d

Seizure Disorders† Oral

8–30 mg/kg daily in divided doses has been used.a c

Edema† Oral or IV

5 mg/kg or 150 mg/m2 once daily in the morning has been used.a

Adults

Glaucoma Open-angle Glaucoma Oral

Conventional tablets: 250 mg to 1 g daily.c For daily dosages >250 mg, administer in divided doses.c

Extended-release capsules: 500 mg twice daily.d

IV

250 mg to 1 g daily.e For daily dosages >250 mg, administer in divided doses.e

Secondary Glaucoma Oral

Conventional tablets: 250 mg every 4 hours.c Some patients respond to short-term therapy with 250 mg twice daily.c

Extended-release capsules: 500 mg twice daily.d

IV

250 mg every 4 hours.e Some patients respond to short-term therapy with 250 mg twice daily.e

Acute Angle-closure Glaucoma Oral

Conventional tablets: 250 mg every 4 hours. a c Alternatively, 250 mg twice daily or an initial dose of 500 mg followed by 125–250 mg every 4 hours.a c

Extended-release capsules: 500 mg twice daily.d

IV

250 mg every 4 hours.e Alternatively, 250 mg twice daily or an initial dose of 500 mg followed by 125–250 mg every 4 hours.e

Acute Mountain Sickness Oral

Conventional tablets and extended-release capsules: 500 mg to 1 g daily in divided doses.c d Initiate 24–48 hours before ascent; continue for 48 hours while at high altitude or longer if needed to control symptoms.c d

125–250 mg twice daily starting 24 hours before ascent has been effective for prevention of acute mountain sickness; 500 mg (as extended-release capsules) every 24 hours also has been effective.f 750 mg daily may be more effective than 500 mg daily.f

125 mg at bedtime has been used for the management of high-altitude sleep disorders.f

For treatment of acute mountain sickness, some experts recommend 250 mg given within 24 hours of onset of symptoms and a second 250-mg dose 8 hours later.f

Seizure Disorders Oral

Conventional tablets: 8–30 mg/kg daily in divided doses.c

Usual dosage range: 375 mg to 1 g daily.c

When used in conjunction with other anticonvulsants, initiate at 250 mg once daily and increase dosage as needed.c

IV

8–30 mg/kg daily in divided doses; usual dosage range is 375 mg to 1 g daily.e

When given in conjunction with other anticonvulsants, initiate at 250 mg once daily and increase dosage as needed.e

Edema CHF Oral

Conventional tablets: Initially, 250–375 mg (5 mg/kg) once daily in the morning.c

If patient fails to lose edema fluid after initial response, hold drug for 1 day. c To avoid loss of diuretic effect, administer intermittently (on alternate days or for 2 days followed by a drug-free day).c

IV

Initially, 250–375 mg (5 mg/kg) once daily in the morning.e

If patient fails to lose edema fluid after initial response, hold drug for 1 day.e To avoid loss of diuretic effect, administer intermittently (on alternate days or for 2 days followed by a drug-free day).e

Drug-induced Edema Oral

Conventional tablets: 250–375 mg once daily for 1 or 2 days, alternating with a drug-free day.c

IV

250–375 mg once daily for 1 or 2 days, alternating with a drug-free day.e

Periodic Paralysis† Oral

250 mg 2 to 3 times daily has been used.a

Prescribing Limits

When used in glaucoma or seizure disorders, dosage >1 g daily is not associated with additional clinical benefit.c d e

When used for diuresis, increasing dosage does not produce greater response and may result in decreased response.c d e

Special Populations

Geriatric Patients

Select dosage with caution because of age-related decreases in hepatic, renal, and/or cardiac function and concomitant disease and drug therapy.d

Acetazolamide Sodium Pharmacokinetics

Absorption

Bioavailability

Well absorbed from GI tract.a b Peak plasma concentrations attained within 1–4 or 3–6 hours following administration of conventional tablets or extended-release capsules, respectively.d

Onset

Following IV administration, reduction in IOP occurs in 2 minutes.b

Following administration of conventional tablets or extended-release capsules, reduction in IOP occurs in 1 or 2 hours, respectively.b

Duration

Following IV administration, reduction in IOP persists for 4–5 hours.b

Following administration of conventional tablets or extended-release capsules, reduction in IOP persists for 8–12 or 18–24 hours, respectively.b d

Food

Extended-release capsules: Food does not affect absorption.d

Distribution

Extent

Distributed into erythrocytes, renal cortex, and aqueous humor of eye.a d

Crosses the placenta.a b

Distributed into milk in dogs; not known whether distributed into human milk.a

Elimination

Elimination Route

Excreted principally in the urine as unchanged drug.a

Stability

Storage

Oral

Tablets

Tight, light-resistant container at 15–30°C.c

Capsules

20–25°C.d

Parenteral

Powder for Injection

15–30°C.e

Reconstituted solutions prepared using sterile water for injection are stable for 3 days at 2–8°C or 12 hours at 15–30°C.e

Use reconstituted solutions within 12 hours to minimize the risk of microbial contamination.e

Compatibility

For information on systemic interactions resulting from concomitant use, see Interactions.

Parenteral

Solution CompatibilityHID

Compatible

Dextrose–Ringer’s injection combinations

Dextrose-Ringer’s injection, lactated, combinations

Dextrose-saline combinations

Dextrose 2½, 5, or 10% in water

Ionosol products

Ringer’s injection

Ringer’s injection, lactated

Sodium chloride 0.45 or 0.9%

Sodium lactate (1/6) M

Drug CompatibilityHID Admixture Compatibility

Compatible

Ranitidine HCl

Y-Site Compatibility

Variable

Diltiazem HCl

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