From the Guidelines
Acetazolamide is primarily indicated for glaucoma, altitude sickness, idiopathic intracranial hypertension, and certain types of seizures, as well as for the treatment of obstructive sleep apnea (OSA) as evidenced by a recent study 1.
Indications for Acetazolamide
- Glaucoma: reduces intraocular pressure by decreasing aqueous humor production, typically dosed at 250-1000 mg daily in divided doses.
- Altitude sickness prevention: given at 125-250 mg twice daily starting 24-48 hours before ascent and continuing for 48 hours at high altitude.
- Idiopathic intracranial hypertension: doses range from 250-1000 mg daily to reduce cerebrospinal fluid production, with a popular starting dose of 250–500 mg twice a day 1.
- Seizure disorders: particularly absence, myoclonic, and atonic seizures, it's used as adjunctive therapy at 8-30 mg/kg/day in children.
- Obstructive sleep apnea (OSA): acetazolamide has been found to reduce sleep apnea intensity (AHI) by up to 45% in unselected groups of patients 1.
- Metabolic alkalosis, periodic paralysis, and as a diuretic in heart failure when other diuretics have failed.
Important Considerations
- The medication works as a carbonic anhydrase inhibitor, which affects ion transport and fluid balance across various membranes in the body.
- Common side effects include paresthesias, fatigue, altered taste, and increased urination.
- It should be used cautiously in patients with sulfa allergies, kidney disease, liver disease, or electrolyte imbalances.
- In patients with pre-existing cardiovascular conditions, acetazolamide administration seems to reduce the risk of subendocardial ischaemia at high altitude, and thus use of acetazolamide for AMS prevention might be helpful 1.
From the FDA Drug Label
Acetazolamide is a potent carbonic anhydrase inhibitor, effective in the control of fluid secretion (e.g., some types of glaucoma), in the treatment of certain convulsive disorders (e.g., epilepsy) and in the promotion of diuresis in instances of abnormal fluid retention (e.g., cardiac edema). In the eye, this inhibitory action of acetazolamide decreases the secretion of aqueous humor and results in a drop in intraocular pressure, a reaction considered desirable in cases of glaucoma and even in certain non-glaucomatous conditions. Evidence seems to indicate that acetazolamide has utility as an adjuvant in treatment of certain dysfunctions of the central nervous system (e.g., epilepsy). The indications for Acetazolamide are:
- Glaucoma: to decrease intraocular pressure
- Epilepsy: as an adjuvant in treatment of certain convulsive disorders
- Abnormal fluid retention: to promote diuresis in instances of cardiac edema 2
From the Research
Indications for Acetazolamide
The indications for Acetazolamide, a carbonic anhydrase inhibitor, include:
- Epilepsy 3
- Glaucoma 3, 4
- Edema 3
- Altitude sickness 3, 5, 6, 7
- Idiopathic intracranial hypertension 3
- Elevated intracranial pressure (ICP) due to cerebrospinal fluid (CSF) leaks 3
- Prevention of high-altitude illness (HAI) 5, 6
- Acute mountain sickness (AMS) 6, 7
- Sleep apnoea 4
Mechanism of Action
Acetazolamide works by inhibiting carbonic anhydrase, leading to:
- Reduced hydrogen ion secretion in the proximal renal tubule 3
- Increased bicarbonate and cation excretion 3
- Urinary alkalization and diuresis 3
- Decreased production of cerebrospinal fluid (CSF) and aqueous humor 3
- Reduced intracranial pressure (ICP) and intraocular pressure 3
Dosage and Administration
The dosage of Acetazolamide ranges from 250 to 4,000 mg daily, divided every 6-12 hours 3. The plasma half-life is 4-8 hours, but the pharmacologic effects last longer 3. Administration should not be more frequent than every 12 hours if creatinine clearance is less than 50 mL/min 3. A dose of 125 mg every 12 hours is effective for preventing high-altitude illness 5, while a dose of 250 mg/day has similar efficacy to higher doses for preventing acute mountain sickness 6.