Acetazolamide

Name: Acetazolamide

Why is this medication prescribed?

Acetazolamide is used to treat glaucoma, a condition in which increased pressure in the eye can lead to gradual loss of vision. Acetazolamide decreases the pressure in the eye. Acetazolamide is also 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 is sometimes prescribed for other uses; ask your doctor or pharmacist for more information.

What should I discuss with my healthcare provider before taking acetazolamide?

You should not use acetazolamide if you are allergic to it, or if you have:

  • severe liver disease, or cirrhosis;

  • severe kidney disease;

  • an electrolyte imbalance (such as acidosis or low levels of potassium or sodium in your blood);

  • adrenal gland failure; or

  • an allergy to sulfa drugs.

To make sure acetazolamide is safe for you, tell your doctor if you have:

  • severe breathing problems;

  • angle closure glaucoma; or

  • if you also take aspirin in high doses.

It is not known whether this medicine will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

Acetazolamide can pass into breast milk and may harm a nursing baby. You should not breast-feed while using this medicine.

Acetazolamide is not approved for use by anyone younger than 18 years old.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Uses for Acetazolamide

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

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

Acetazolamide Description

Acetazolamide, an inhibitor of the enzyme carbonic anhydrase, is a white to faintly yellowish white crystalline, odorless powder, weakly acidic, very slightly soluble in water and slightly soluble in alcohol. The chemical name for Acetazolamide is N-(5-Sulfamoyl-1, 3, 4-thiadiazol-2yl)-acetamide and has the following structural formula:

MW 222.25                                  C4H6N4O3S2

Acetazolamide is available for intravenous use, and is supplied as a sterile powder requiring reconstitution. Each vial contains Acetazolamide sodium equivalent to 500 mg of Acetazolamide. The bulk solution is adjusted to pH 9.6 using sodium hydroxide NF and, if necessary, hydrochloric acid NF prior to lyophilization.

Indications and Usage for Acetazolamide

For adjunctive treatment of: edema due to congestive heart failure; drug-induced edema; centrencephalic epilepsies (petit mal, unlocalized seizures); chronic simple (open-angle) glaucoma, secondary glaucoma, and preoperatively in acute angle-closure glaucoma where delay of surgery is desired in order to lower intraocular pressure.

Overdosage

No data are available regarding Acetazolamide overdosage in humans as no cases of acute poisoning with this drug have been reported.

Animal data suggest that Acetazolamide is remarkable nontoxic. No specific antidote is known. Treatment should be symptomatic and supportive.

Electrolyte imbalance, development of an acidotic state, and central nervous effects might be expected to occur. Serum electrolyte levels (particularly potassium) and blood pH levels should be monitored.

Supportive measures are required to restore electrolyte and pH balance. The acidotic state can usually be corrected by the administration of bicarbonate.

Despite its high intraerythrocytic distribution and plasma protein binding properties, Acetazolamide may be dialyzable. This may be particularly important in the management of Acetazolamide overdosage when complicated by the presence of renal failure.

Pharmacology

Reversible inhibition of the enzyme carbonic anhydrase resulting in reduction of hydrogen ion secretion at renal tubule and an increased renal excretion of sodium, potassium, bicarbonate, and water. Decreases production of aqueous humor and inhibits carbonic anhydrase in central nervous system to retard abnormal and excessive discharge from CNS neurons.

Absorption

Appears to be dose dependent; erratic with daily doses >10 mg/kg

Distribution

Erythrocytes, kidneys; blood-brain barrier and placenta; distributes into milk (~30% of plasma concentrations)

Excretion

Urine (70% to 100% [IV, tablet], 47% [extended release capsule] as unchanged drug within 24 hours)

Onset of Action

Capsule (extended release): 2 hours; Tablet (immediate release): 1 to 1.5 hours; IV: 2 to 10 minutes

Peak effect: Capsule (extended release): 8 to 18 hours; IV: 15 minutes; Tablet: 2 to 4 hours

Time to Peak

Plasma: Capsule (extended release): 3 to 6 hours; Tablet: 1 to 4 hours; IV: 15 minutes

Duration of Action

Inhibition of aqueous humor secretion: Capsule (extended release): 18 to 24 hours; IV: 4 to 5 hours; Tablet: 8 to 12 hours

Half-Life Elimination

2.4 to 5.8 hours

Protein Binding

95%

Use Labeled Indications

Treatment of glaucoma (chronic simple open-angle, secondary glaucoma, preoperatively in acute angle-closure); drug-induced edema or edema due to congestive heart failure (adjunctive therapy; IV and immediate release dosage forms); centrencephalic epilepsies (IV and immediate release dosage forms); prevention or amelioration of symptoms associated with acute mountain sickness (immediate and extended release dosage forms)

Acetazolamide Overview

Acetazolamide is a prescription medication used to treat glaucoma and symptoms of acute mountain sickness. Acetazolamide is used with other medicines to reduce edema (excess fluid retention) and to help control seizures in certain types of epilepsy. Acetazolamide belongs to a group of drugs called carbonic anhydrase inhibitors, which help to reduce amount of fluid in the eye and to reduce adverse symptoms when at high altitudes.

This medication comes in tablet and an extended release capsule form, and is taken with or without food.

Acetazolamide also available in an injectable form to be given directly into a vein (IV) by a healthcare professional.

Common side effects of acetazolamide include rash, fever, and reduced field of vision. Acetazolamide may cause dizziness, drowsiness, or blurred vision. Do not drive or operate heavy machinery until you know how acetazolamide affect you.

Acetazolamide and Lactation

Tell your doctor if you are breastfeeding or plan to breastfeed.

Because of the possibility for serious negative reactions in nursing infants from acetazolamide, a decision should be made whether to stop nursing or to stop the drug. Acetazolamide should only be used by nursing women if the benefit outweighs the risk to the child.

Acetazolamide Overdose

If you take too much of this medication, call your healthcare provider or local Poison Control Center, or seek emergency medical attention right away.

If acetazolamide is administered by a healthcare provider in a medical setting, it is unlikely that an overdose will occur. However, if overdose is suspected, seek emergency medical attention.

Pregnancy & Lactation

Pregnancy category: C

Lactation: Enters breast milk; not recommended

Pregnancy Categories

A:Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B:May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C:Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D:Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X:Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA:Information not available.

For Healthcare Professionals

Applies to acetazolamide: compounding powder, injectable powder for injection, intravenous powder for injection, oral capsule extended release, oral tablet

General

Adverse reactions occurring early in therapy have included paresthesias, tinnitus, nausea, vomiting, diarrhea, and drowsiness.[Ref]

Hypersensitivity

Frequency not reported: Anaphylactic/anaphylactoid reactions including shock and fatalities[Ref]

Hematologic

Frequency not reported: Blood dyscrasias such as aplastic anemia, agranulocytosis, leucopenia, thrombocytopenia, and thrombocytopenia purpura[Ref]

Metabolic

Frequency not reported: Loss of appetite, electrolyte disturbances, metabolic acidosis and hypokalemia with long term therapy, hyponatremia osteomalacia with long-term therapy, hyper/hypoglycemia[Ref]

Dermatologic

Rare (0.01% to 0.1%): Photosensitivity
Frequency not reported: Skin reactions, Stevens-Johnson syndrome, toxic epidermal necrolysis, urticaria, rash including erythema multiforme[Ref]

Gastrointestinal

Frequency not reported: Nausea, vomiting, diarrhea, melena[Ref]

Hepatic

Frequency not reported: Abnormal liver function, cholestatic jaundice, fulminant hepatic necrosis, hepatitis[Ref]

Nervous system

Very common (10% or more): Paresthesias (up to 20%)
Frequency not reported: Drowsiness, headache, dizziness, taste alteration, ataxia, flaccid paralysis, convulsions, sensory disturbances[Ref]

Psychiatric

Frequency not reported: Confusion, irritability, depression, excitement, reduced libido[Ref]

Ocular

Frequency not reported: Transient myopia[Ref]

Renal

Frequency not reported: Renal colic, increased risk of nephrolithiasis, renal failure[Ref]

Genitourinary

Frequency not reported: Polyuria, polydipsia, crystalluria, renal calculi, hematuria, glycosuria[Ref]

Musculoskeletal

Frequency not reported: Growth retardation in children[Ref]

Other

Frequency not reported: Flushing, malaise, thirst, fatigue, fever, hearing disturbances[Ref]

Local

Frequency not reported: Injection site pain[Ref]

Some side effects of acetazolamide may not be reported. Always consult your doctor or healthcare specialist for medical advice. You may also report side effects to the FDA.

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.

Acetazolamide Breastfeeding Warnings

Benefit should outweigh risk Excreted into human milk: Yes

Based on single case reports, low levels of this drug are expected in human milk. The infants estimated dose from a maternal dose of 1000 mg a day (sustained-release product) is less than 0.7% of the maternal weight-adjusted dose. Some authorities believe this drug is compatible with breastfeeding when used to treat glaucoma. However, product manufacturers advise against, or advise use with extreme caution while breastfeeding due to the potential for serious adverse effects in nursing infants.

Acetazolamide Identification

Substance Name

Acetazolamide

CAS Registry Number

59-66-5

Drug Class

Anticonvulsants

Antiglaucoma Agents

Carbonic Anhydrase Inhibitors

Diuretics

Administrative Information

LactMed Record Number

489

Last Revision Date

20130907

Disclaimer

Information presented in this database is not meant as a substitute for professional judgment. You should consult your healthcare provider for breastfeeding advice related to your particular situation. The U.S. government does not warrant or assume any liability or responsibility for the accuracy or completeness of the information on this Site.

(web3)