Acetazolamide

Name: Acetazolamide

Acetazolamide dosing information

Usual Adult Dose for Edema:

Initial dose: 250 to 375 mg orally/IV once a day
-If after initial response there is a lack of response, hold therapy for a day
Maintenance dose: One dose every other day or once a day for 2 days alternating with a day of rest

Comments:
-Best diuretic results are obtained when taken on alternate days or when taken once daily for 2 days alternating with a day of rest.
-Too frequent dosage or too high a dose may result in therapeutic failure.
-For diuresis in congestive heart failure, the starting dose is approximately 5 mg/kg.

Uses: For adjunctive treatment of edema due to congestive heart failure or drug-induced edema.

Usual Adult Dose for Acute Mountain Sickness:

500 to 1000 mg orally per day in divided doses
-May use immediate-release or extended-release as appropriate

Acute Mountain Sickness (AMS)/High Altitude Cerebral Edema (HACE) Prevention:
Guideline dose: 125 mg orally twice a day

AMS Treatment:
Guideline dose: 250 mg orally twice a day

Comments:
-Higher doses (1000 mg) are appropriate for rapid ascent, such as in rescue or military operations.
-Dosing should be to initiated 24 to 48 hours before ascent and continue for 48 hours while at high altitude, or longer as necessary to control symptoms.
-According to Wilderness Medical Society Consensus Guidelines, while higher doses are effective they are associated with more frequent and/or increased side effects.

Use: For the prevention or amelioration of symptoms associated with acute mountain sickness despite gradual ascent.

Usual Adult Dose for Glaucoma:

Open-Angle Glaucoma:
-Immediate-release (IR) tablets: 250 to 1000 mg orally per day; amounts over 250 mg should be administered in divided doses
-Extended-release (ER) capsules: 500 mg orally 2 times a day
Maintenance: Adjust doses individually based on symptomatology and ocular tension; for patients inadequately controlled on ER capsules 1 g/day, may supplement with IR tablets
-Doses in excess of 1 g/24 hours generally do not produce increased effects

Preoperatively in Closed-Angle Glaucoma:
-Various regimens have been used including: 250 mg orally every 4 hours; 250 mg orally twice a day; OR 500 mg orally followed by 125 mg or 250 mg orally every 4 hours

Comments:
-In acute cases, IV therapy (at same oral dosage) has been used for rapid relief of ocular tension.
-A complementary effect has been observed when used in conjunction with miotics or mydriatics.

Uses: For the adjunctive treatment of chronic simple (open-angle) glaucoma, secondary glaucoma, and preoperatively in acute angle-closure glaucoma where a delay of surgery is desirable so as to decrease intraocular pressure.

Usual Adult Dose for Glaucoma (Open Angle):

Open-Angle Glaucoma:
-Immediate-release (IR) tablets: 250 to 1000 mg orally per day; amounts over 250 mg should be administered in divided doses
-Extended-release (ER) capsules: 500 mg orally 2 times a day
Maintenance: Adjust doses individually based on symptomatology and ocular tension; for patients inadequately controlled on ER capsules 1 g/day, may supplement with IR tablets
-Doses in excess of 1 g/24 hours generally do not produce increased effects

Preoperatively in Closed-Angle Glaucoma:
-Various regimens have been used including: 250 mg orally every 4 hours; 250 mg orally twice a day; OR 500 mg orally followed by 125 mg or 250 mg orally every 4 hours

Comments:
-In acute cases, IV therapy (at same oral dosage) has been used for rapid relief of ocular tension.
-A complementary effect has been observed when used in conjunction with miotics or mydriatics.

Uses: For the adjunctive treatment of chronic simple (open-angle) glaucoma, secondary glaucoma, and preoperatively in acute angle-closure glaucoma where a delay of surgery is desirable so as to decrease intraocular pressure.

Usual Adult Dose for Seizure Prophylaxis:

Initial dose: 8 to 30 mg/kg orally/IV in divided doses
Range: 375 to 1000 mg per day

Initial dose for patients on other anticonvulsants: 250 mg orally/IV once a day

Comments:
-The above range represents an optimum range for most patients; some patients respond to a lower dose; for most patients, doses in excess of 1 g do not appear to produce better results.
-Children with petit mal have had the best results; good results have been seen in both children and adult with other seizures such as grand mal, mixed seizure pattern, myoclonic jerk patterns, etc.
-Extended-release capsules are not indicated for use in this condition.

Use: For the adjunct treatment of centrencephalic epilepsies such as petit mal, and unlocalized seizures.

Usual Pediatric Dose for Acute Mountain Sickness:

12 years or older:
Extended-release capsules: 500 mg orally once or twice a day

Guideline dose (immediate-release): 2.5 mg/kg orally every 12 hours
Maximum: 125 mg per dose

Comments:
-Therapy should be initiated 24 to 48 hours before ascent and continued for 48 hours while at high altitude, or longer as necessary to control symptoms.
-Guideline dose is from the Wilderness Medical Society Consensus Guidelines; according to Wilderness Medical Society Consensus Guidelines, higher doses are effective but they are associated with more frequent and/or increased side effects.

Use: For the prevention or amelioration of symptoms associated with acute mountain sickness despite gradual ascent.

Usual Pediatric Dose for Glaucoma:

12 years or older:
Extended-release (ER) capsules: 500 mg orally 2 times a day

Comments: Doses in excess of 1 g/24 hours generally do not produce increased effects.

Uses: For the adjunctive treatment of chronic simple (open-angle) glaucoma, secondary glaucoma, and preoperatively in acute angle-closure glaucoma where a delay of surgery is desirable so as to decrease intraocular pressure.

Usual Pediatric Dose for Glaucoma (Open Angle):

12 years or older:
Extended-release (ER) capsules: 500 mg orally 2 times a day

Comments: Doses in excess of 1 g/24 hours generally do not produce increased effects.

Uses: For the adjunctive treatment of chronic simple (open-angle) glaucoma, secondary glaucoma, and preoperatively in acute angle-closure glaucoma where a delay of surgery is desirable so as to decrease intraocular pressure.

Pronunciation

(a set a ZOLE a mide)

Pharmacologic Category

  • Anticonvulsant, Miscellaneous
  • Carbonic Anhydrase Inhibitor
  • Diuretic, Carbonic Anhydrase Inhibitor
  • Ophthalmic Agent, Antiglaucoma

Dosing Hepatic Impairment

Use contraindicated in patients with cirrhosis or marked liver disease or dysfunction.

Test Interactions

May cause false-positive results for urinary protein with Albustix®, Labstix®, Albutest®, Bumintest®; interferes with HPLC theophylline assay and serum uric acid levels; may lead to false-negative aldosterone/renin ratio (ARR) (Funder 2016)

Uses of Acetazolamide

Acetazolamide is a prescription medication used to treat glaucoma. Acetazolamide is used to reduce the severity and duration of symptoms (upset stomach, headache, shortness of breath, dizziness, drowsiness, and fatigue) of altitude (mountain) sickness. Acetazolamide is used with other medicines to reduce edema (excess fluid retention) and to help control seizures in certain types of epilepsy.

This medication may be prescribed for other uses. Ask your doctor or pharmacist for more information.

Acetazolamide Drug Class

Acetazolamide is part of the drug class:

  • Carbonic anhydrase inhibitors

Acetazolamide Precautions

Serious side effects have been reported with acetazolamide including:

  • paresthesias, particularly a “tingling” feeling in the extremities. Occurs most often early in therapy.
  • tinnitus (noise or ringing in the ears)
  • hypersensitivity (severe allergic reaction). Signs of a hypersensitivity reaction, which include the following:
    • chest pain
    • swelling of the face, eyes, lips, tongue, arms, or legs
    • difficulty breathing or swallowing
    • fainting
    • rash
  • loss of blood sugar control. Caution is advised in those with impaired glucose (blood sugar) tolerance or in those with diabetes.
  • electrolyte imbalances. Electrolytes are minerals in your body that help your body function normally. An imbalance could lead to abnormalities such as arrhythmias (with low or high levels of potassium), a change in body fluid (due to low or high levels of sodium), and altered acidity levels of your blood.
  • anaphylaxis, fever, rash (including erythema multiforme, Stevens-Johnson syndrome, toxic epidermal necrolysis)
  • decrease in blood counts

Acetazolamide may cause dizziness, drowsiness, or blurred vision. Do not drive or operate heavy machinery until you know how acetazolamide affect you.

Do not take acetazolamide if you:

  • have an allergic reaction to acetazolamide or any of its ingredients
  • have a history of an allergic reaction to sulfonamides
  • have lowered levels of sodium and/or potassium blood levels in cases of kidney and liver disease or dysfunction, in suprarenal gland failure, and in hyperchloremic acidosis
  • have a history of cirrhosis because of the risk of development of hepatic encephalopathy
  • are using acetazolamide for a prolonged duration and also have chronic non-congestive angle-closure glaucoma

Usual Adult Dose for Edema

Initial dose: 250 to 375 mg orally/IV once a day
-If after initial response there is a lack of response, hold therapy for a day
Maintenance dose: One dose every other day or once a day for 2 days alternating with a day of rest

Comments:
-Best diuretic results are obtained when taken on alternate days or when taken once daily for 2 days alternating with a day of rest.
-Too frequent dosage or too high a dose may result in therapeutic failure.
-For diuresis in congestive heart failure, the starting dose is approximately 5 mg/kg.

Uses: For adjunctive treatment of edema due to congestive heart failure or drug-induced edema.

Usual Adult Dose for Seizure Prophylaxis

Initial dose: 8 to 30 mg/kg orally/IV in divided doses
Range: 375 to 1000 mg per day

Initial dose for patients on other anticonvulsants: 250 mg orally/IV once a day

Comments:
-The above range represents an optimum range for most patients; some patients respond to a lower dose; for most patients, doses in excess of 1 g do not appear to produce better results.
-Children with petit mal have had the best results; good results have been seen in both children and adult with other seizures such as grand mal, mixed seizure pattern, myoclonic jerk patterns, etc.
-Extended-release capsules are not indicated for use in this condition.

Use: For the adjunct treatment of centrencephalic epilepsies such as petit mal, and unlocalized seizures.

Usual Pediatric Dose for Glaucoma

12 years or older:
Extended-release (ER) capsules: 500 mg orally 2 times a day

Comments: Doses in excess of 1 g/24 hours generally do not produce increased effects.

Uses: For the adjunctive treatment of chronic simple (open-angle) glaucoma, secondary glaucoma, and preoperatively in acute angle-closure glaucoma where a delay of surgery is desirable so as to decrease intraocular pressure.

Liver Dose Adjustments

Contraindicated in marked liver disease of impairment

Dose Adjustments

Contraindicated in marked renal disease or impairment (specific CrCl level not provided, however, less than 10 mL/min has been provided by some authorities)

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