Acetazolamide Sodium

Name: Acetazolamide Sodium

Cautions for Acetazolamide Sodium

Contraindications

  • Marked impairment of hepatic function.c d e Cirrhosis.c d e (See Hepatic Impairment under Cautions.)

  • Depressed serum concentrations of sodium and/or potassium.c d e

  • Adrenocortical insufficiency.c d e

  • Hyperchloremic acidosis.c d e

  • Marked impairment of renal function.c d e

  • Long-term treatment of angle-closure glaucoma; further closure of the angle may occur while worsening of glaucoma is masked by lower IOP.b c d e

  • Hypersensitivity to acetazolamide or any ingredients in the formulation.c d e

Warnings/Precautions

Sensitivity Reactions

Sulfonamide Sensitivity Reactions

Serious adverse events (e.g., Stevens-Johnson syndrome, toxic epidermal necrolysis, fulminant hepatic necrosis, agranulocytosis, aplastic anemia, other blood dyscrasias) associated with sulfonamide therapy possible.b c d e

Discontinue if signs of hypersensitivity, blood dyscrasias, or other serious reactions occur.b c e

General Precautions

CNS Effects

Drowsiness and/or paresthesia reported with high dosages.b c d e

Respiratory Effects

Caution in patients with pulmonary obstruction, emphysema, or advanced pulmonary disease where alveolar ventilation may be impaired.b c d e Acetazolamide may precipitate or aggravate acidosis in these patients.c d e

Laboratory Monitoring

Monitor for hematologic reactions associated with sulfonamides; obtain a CBC and platelet count before therapy and periodically during therapy.c d e Discontinue the drug if clinically important changes occur.c d e

Monitor serum electrolytes periodically for electrolyte imbalances (i.e., hyponatremia, hypokalemia, metabolic acidosis).c d e

Glucose Concentrations

Increased or decreased blood glucose concentrations reported.d Caution in patients with impaired glucose tolerance or diabetes mellitus.b

Specific Populations

Pregnancy

Category C.c d e

Lactation

Discontinue nursing or the drug.c d e

Pediatric Use

Conventional tablets and parenteral preparation: Manufacturers state that safety and efficacy not established.c e

Extended-release capsules: Safety and efficacy not established in pediatric patients <12 years of age. d

Growth retardation has been reported in children receiving long-term therapy with extended-release capsules.d

Geriatric Use

Risk of metabolic acidosis (may be severe) in geriatric patients with reduced renal function.d

Hepatic Impairment

Avoid use in patients with marked hepatic impairment, including those with cirrhosis, because of the risk of developing hepatic encephalopathy.c d e (See Contraindications.)

Renal Impairment

Avoid use in patients with marked renal impairment.c d e (See Contraindications.)

Common Adverse Effects

Paresthesias, hearing dysfunction or tinnitus, anorexia, altered taste, nausea, vomiting, diarrhea, polyuria, drowsiness, confusion.c e

Interactions for Acetazolamide Sodium

Specific Drugs and Laboratory Tests

Drug or Test

Interaction

Comments

Amphetamine

Decreased urinary excretion of amphetamines; potentiates the effects of amphetaminesd

Amphotericin B

Possible enhanced potassium depletionb

Antidiabetic agents (oral agents, insulin)

May interfere with the hypoglycemic responseb

Aspirin

Increased risk of toxicityc d e

Avoid concomitant use in patients receiving high-dose aspirinc d e h

Carbonic anhydrase inhibitors, topical

Additive systemic effectsd g

Concomitant use not recommendedd g

Corticosteroids

Possible enhanced potassium depletionb

Cyclosporine

Possible increased plasma cyclosporine concentrationsd

Digitalis glycosides

Acetazolamide-induced hypokalemia may potentiate toxicity of digitalisb

Folic acid antagonists

Potential antifolate effectd

Lithium

Increased renal excretion of lithium and decreased lithium concentrationsd

Monitor patientb

Methenamine

May interfere with urinary antiseptic effect of methenamined

Phenytoin

Altered metabolism of phenytoin; increased serum phenytoin concentrations; increased risk of phenytoin-associated osteomalaciab d

Caution advisedd

Primidone

Possible decreased serum concentration of primidone and its metabolites; possible decreased anticonvulsant effectd

Caution advisedd

Quinidine

Decreased urinary excretion of quinidined

Sodium bicarbonate

Increased risk of renal calculusd

Tests for urinary protein

False-positive results with tests that use bromophenol blue reagent (Albustix) or sulfosalicylic acidb

Tests, theophylline concentrations

Interferes with high-performance liquid chromatography (HPLC) assay for theophyllined

Actions

  • Noncompetitive reversible inhibitor of the carbonic anhydrase enzyme.b d c e

  • Reduces the formation of hydrogen and bicarbonate ions from carbon dioxide and water, thereby reducing availability of these ions for active transport into secretions.b

  • Decreases aqueous humor secretion and IOP.b c d

  • Increases urinary excretion of bicarbonate, sodium, and potassium due to decrease in hydrogen ions in the renal tubules.b Decreases reabsorption of water, increases urine volume, urine becomes alkaline.b

  • When used as a diuretic, plasma bicarbonate concentration is decreased and chloride concentration may be increased, resulting in metabolic acidosis.b In the presence of acidosis, diuretic effect ceases.b

  • In acute mountain sickness, the effect of acetazolamide on acid-base balance (i.e., increased renal excretion of bicarbonate that leads to metabolic acidosis) results in compensatory hyperventilation and improved oxygenation.f

  • Exact mechanism of anticonvulsant activity unclear; may be due to metabolic acidosis, inhibition of carbonic anhydrase in the CNS, or other mechanisms.b

Advice to Patients

  • Risk of adverse effects, including sensitivity reactions; discontinue therapy and consult clinician if signs of sensitivity occur.c d e

  • When used to prevent acute mountain sickness, importance of gradual ascent.c f Use of acetazolamide does notobviate need to stop ascent if acute mountain sickness develops or descend if severe forms of altitude sickness (e.g., high attitude pulmonary or cerebral edema) occur.c f

  • Potential for the drug to impair mental alertness or impair vision (myopia); use caution when driving a vehicle or operating machinery until effects on individual are known.d

  • Advise patients with pulmonary obstruction or emphysema that the drug may precipitate or aggravate acidosis.c d

  • Advise patients with diabetes or impaired glucose tolerance that increases and decreases in blood glucose have occurred in acetazolamide-treated patients.d

  • Importance of informing clinicians of existing or contemplated concomitant therapy, including prescription and OTC drugs (e.g., high-dose aspirin), as well as concomitant diseases.c d e

  • Importance of women informing clinicians if they are or plan to become pregnant or plan to breast-feed.c d e

  • Importance of informing patients of other precautionary information.c d e (See Cautions.)

Preparations

Excipients in commercially available drug preparations may have clinically important effects in some individuals; consult specific product labeling for details.

Please refer to the ASHP Drug Shortages Resource Center for information on shortages of one or more of these preparations.

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

acetaZOLAMIDE

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Oral

Capsules, extended-release*

500 mg*

Diamox

Duramed

Tablets

125 mg*

Acetazolamide Tablets

250 mg*

Acetazolamide Tablets

* available from one or more manufacturer, distributor, and/or repackager by generic (nonproprietary) name

acetaZOLAMIDE Sodium

Routes

Dosage Forms

Strengths

Brand Names

Manufacturer

Parenteral

For injection, for IV use

500 mg (of acetazolamide)*

Acetazolamide Sodium for Injection

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