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SENSORY ORGANS › OPHTHALMOLOGICALS › ANTIGLAUCOMA PREPARATIONS AND MIOTICS › Carbonic anhydrase inhibitors
acetazolamide
S01EC01
Forms & Strengths
- Tablet: 125 mg, 250 mg
- Capsule, extended-release: 500 mg
- Injection, powder for reconstitution: 500 mg/vial
Adult Dosing
- Glaucoma: 250 mg to 1 g daily in divided doses
- Epilepsy: 840 mg to 30 g daily in divided doses
- Acute mountain sickness: 250 mg every 8 to 12 hours (or 500 mg ER every 12 hours) starting 24-48 hours before ascent
- Edema of heart failure: 250 mg to 375 mg once daily in the morning
- Idiopathic intracranial hypertension: 1 g to 2 g daily in divided doses
Pediatric Dosing
- Glaucoma: 8 to 30 mg/kg/day in divided doses every 6 to 8 hours
- Epilepsy: 8 to 30 mg/kg/day in divided doses up to 750 mg daily
- Acute mountain sickness: 2.5 mg/kg every 8 to 12 hours starting before ascent
Indications
- Open-angle, secondary, and acute angle-closure glaucoma
- Adjunctive treatment of epilepsy (absence, generalized tonic-clonic)
- Prevention and treatment of acute mountain sickness
- Edema due to congestive heart failure or drug-induced edema
- Idiopathic intracranial hypertension (pseudotumor cerebri)
Mechanism of Action
- Reversible inhibition of the enzyme carbonic anhydrase in the ciliary body of the eye, reducing aqueous humor secretion and intraocular pressure
- Inhibition of renal carbonic anhydrase decreases active transport of sodium across proximal tubules, causing increased excretion of sodium, potassium, bicarbonate, and water
- Inhibition of brain carbonic anhydrase delays abnormal, paroxysmal central nervous system discharge in epilepsy
- Reduces cerebrospinal fluid production in the choroid plexus
Contraindications
- Hypersensitivity to acetazolamide or sulfonamides
- Marked hepatic disease or dysfunction
- Severe renal disease or dysfunction (CrCl < 10 mL/min)
- Adrenocortical insufficiency (Addison's disease)
- Hypochloremic acidosis and hypokalemia
Adverse Reactions
- Paresthesias, fatigue, dizziness, drowsiness
- Metabolic acidosis, hypokalemia, hyponatremia, hyperuricemia
- Polyuria, crystalluria, nephrolithiasis
- Taste alteration (dysgeusia), anorexia, nausea, diarrhea
- Rare: Stevens-Johnson syndrome, bone marrow suppression, agranulocytosis
Drug Interactions
- Concurrent use with high-dose aspirin increases risk of severe metabolic acidosis and central nervous system toxicity
- Increases plasma concentrations and toxicity of amphetamines, quinidine, and lithium
- Potentiates toxicity of cardiac glycosides (digoxin) via hypokalemia
- Increases risk of nephrolithiasis when co-administered with calcium channel blockers or other carbonic anhydrase inhibitors (e.g., topiramate)
- Diminishes urinary excretion of weak organic bases and increases excretion of weak organic acids
Curated Content: Needs Vetting Before Put to Clinical Use