Generic Name: Acetazolamide
Brand Name: Diamox, Dazamide, Diamox Sequels, Storzolamide, Acetazolam, Apo-Acetazolamide
Pharmacologic Classification: Carbonic Anhydrase Inhibitor
Therapeutic Classification: antiglaucoma, diuretics, ocular hypotensive agents, anticonvulsants
Indications
- Glaucoma (lowers intraocular pressure in the treatment of glaucoma)
- Epilepsy
- Congestive heart failure
- Drug-induced edema
- Altitude sickness (mountain sickness)
Mechanisms of Action
Acetazolamide is an enzyme inhibitor that acts particularly on carbonic anhydrase. Carbonic anhydrase is the enzyme that converts carbon dioxide and water to carbonic acid (H2CO3). Carbonic anhydrase inhibitors, such as Acetazolamide inhibits carbonic anhydrase in the tissues and fluid thus, decreasing carbonic acid in the body.
In the eye, the inhibitory action of Acetazolamide decreases the secretion of aqueous humor that lowers the intraocular pressure which is desirable in glaucoma. In the central nervous system (CNS), restrained carbonic anhydrase retards the abnormal and paroxysmal excessive discharge from the neurons of CNS.
In the kidneys, carbonic acid is excreted due to the inhibited carbonic anhydrase function. The result is renal loss of bicarbonate which carries out sodium, potassium and water. Alkalinization of urine and diuresis then takes place.
Contraindications
- Hypersensitivity to carbonic anhydrase inhibitor
- Hypersensitivity to sulfonamides
- Depressed levels of serum potassium and sodium
- Marked kidney and liver disease
- Suprarenal grand failure
- Hyperchloremic disease
- First trimester of pregnancy
- Concurrent use of ophthalmic carbonic anhydrase inhibitors (brinzolamide, dorzolamide)
- Adrenal gland failure (Addison’s disease)
- Sickle cell anemia
- Chronic non-congestive glaucoma
Use cautiously in
- Chronic respiratory disease
- Diabetes Mellitus
- Second or third trimester of pregnancy
- Lactation
- History of kidney stones
Adverse Reactions and Side Effects
- Depression
- Tiredness
- Body malaise
- Drowsiness and confusion
- Transient nearsightedness
- Anorexia
- Metallic taste
- Nausea and vomiting
- Crystalluria
- Renal calculi
- Rashes
- Hyperglycemia
- Hyperchloremic acidosis
- Hypokalemia
- Aplastic anemia
- Hemolytic anemia
- Leucopenia
- Weight loss
- Paresthesias
- Tingling feeling of the extremities
- Polyuria
- Polydipsia
- Blushing
- Headache
- Irritability
- Photosensitivity (rare)
Occasional adverse reactions:
- Urticaria
- Melena
- Hematuria
- Glycosuria
- Hepatic insufficiency
- Flaccid paralysis
During long-term therapy, an acidotic state may occasionally appear. This can managed or corrected by the administration of bicarbonate.
Dosage and Route
PO (adults)
Glaucoma: 250-1000 mg/day in 1-4 divided doses (up to 250 mg every 4 hours)
Epilepsy: 4-30 mg/kg/day in 1-4 divided doses
Altitude sickness: 250 mg 2-4 times a day started 24-48 hours before ascent, continued for 48 hours or longer to control symptoms.
PO (Children)
Glaucoma: 8-30 mg/kg/day in 3 divided doses
IM, IV (Adults): 250-500 mg, may repeat in 2-4 hours
IM, IV (children): 5-10 mg/kg every 6 hours
Nursing Management
- 1. Monitor individuals taking acetazolamide with primidone and carbamazepine. Acetazolamide may increase the blood levels of carbamazepine and quinidine and may decrease the blood levels of primidone.
- Instruct the patient to avoid taking aspirin with Acetazolamide. Increase in side effects such as drowsiness, confusion, lethargy, hyperventilation and ringing in the ears when acetazolamide is taken with aspirin.
- Monitor electrolyte levels.
