Acetazolam , Apo-Acetazolamide , Diamox Sequels
Classifications: eye preparation; carbonic anhydrase inhibitor; diuretic; anticonvulsant; Therapeutic: diuretic; anticonvulsant
Pregnancy Category: C
125 mg, 250 mg tablets; 500 mg sustained-release capsules; 500 mg powder for injection
The mechanism of anticonvulsant action is unknown but thought to involve inhibition of CNS carbonic anhydrase, which retards
abnormal transmission from CNS neurons. Diuretic effect is due to inhibition of carbonic anhydrase activity in proximal
renal tubule, preventing formation of carbonic acid, and therefore the formation of H+ and HCO3. Inhibition of carbonic anhydrase in eye reduces rate of aqueous humor formation with consequent lowering of intraocular
Reduces seizure activity and intraocular pressure. Additionally, it has a diuretic effect.
Treatment of seizures: absence or petit mal, generalized tonic-clonic (grand mal), and focal; reduction of intraocular pressure
in open-angle glaucoma and secondary glaucoma; preoperative treatment of acute closed-angle glaucoma; drug-induced edema
and as adjunct in treatment of edema due to congestive heart failure; acute high-altitude sickness.
Prevent uric acid or cystine renal calculi; to treat acute pancreatitis, premenstrual syndrome (PMS), metabolic alkalosis,
and hypokalemic and hyperkalemic forms of familial periodic paralysis; to increase secretion of phenobarbital or lithium;
Hypersensitivity to carbonic anhydrase inhibitors, marked renal and hepatic disease; Addison's disease or other types of
adrenocortical insufficiency; hyponatremia, hypokalemia, hyperchloremic acidosis; prolonged administration to patients with
hyphema; chronic noncongestive angle-closure glaucoma; pregnancy (category C).
Hypersensitivity to sulfonamides and derivatives (e.g., thiazides), history of hypercalciuria; diabetes mellitus, elderly,
gout, patients receiving digitalis, obstructive pulmonary disease, respiratory acidosis.
Route & Dosage
Adult: PO 250 mg 14 times/d, 500 mg sustained release b.i.d., up to 1 g/d IM/IV 500 mg, may repeat in 24 h
Child: PO 830 mg/kg/d in 3 doses IV 510 mg/kg q6h
Adult/Child: PO 830 mg/kg/d in 14 doses
Adult: PO/IV 250375 mg every a.m. (5 mg/kg); may be given every other day if condition improves
Child: PO/IV 5 mg/kg or 150 mg/m2/every a.m.
High Altitude Sickness
Adult: PO 250 mg q812h or 500 mg sustained release q1224h, starting 2448 h before climb and continuing for 48 h at
Neonate/Infant: PO/IV 20 mg/kg/d in divided doses q812h (max: 100 mg/kg/d)
Clcr1050 mL/min: extend interval to q12h; <10 mL/min: use not recommended
Hemodialysis: Administer post-dialysis
- Administer diuretic dose in morning to avoid interrupted sleep.
- Give with food or meals to minimize GI upset.
- Note: If tablet(s) cannot be swallowed, soften tablet(s) (not sustained release form) in 2 tsp of hot water and add to 2 tsp of
honey/syrup to disguise bitter taste; avoid syrups containing alcohol or glycerin, or crush tablet(s) and suspend in syrup
(250500 mg/5 mL syrup). Prepare just before administration. Drug does not dissolve in fruit juices.
- Store oral preparations at 15°30° C (59°86° F) unless otherwise directed.
- Reconstitute as for IV administration. See PREPARE Direct.
- Give IM for rapid lowering of intraocular pressure or in patients unable to take oral dosage.
- Note: The intramuscular dosage is not the route of choice because the alkalinity of the solution makes the injection painful.
- IV administration to neonates, infants, and children: Verify correct IV concentration and rate of infusion/injection with
PREPARE: Direct: Reconstitute each 500 mg vial with at least 5 mL of sterile water for injection to yield approximately 100 mg/mL. IV Infusion: Reconstituted solution may be used as prepared or further diluted with DSW or NS. Use within 24 h of reconstitution.
ADMINISTER: Direct: Give at a rate of 500 mg or fraction thereof over 1 min. IV Infusion: Give as a continuous infusion over 48 h.
INCOMPATIBILITIES Solution/additive: Amino acid. Y-site: Diltiazem, TPN.
Adverse Effects (≥1%)CNS:
Paresthesias, sedation, malaise, disorientation, depression
, muscle weakness, flaccid paralysis. GI:
Anorexia, nausea, vomiting, weight loss, dry mouth, thirst, diarrhea. Hematologic:
Bone marrow depression
with agranulocytosis, hemolytic anemia, aplastic anemia,
leukopenia, pancytopenia. Metabolic:
Increased excretion of calcium, potassium, magnesium, and sodium, metabolic acidosis, hyperglycemia, hyperuricemia. Ocular:
transient myopia. Urogenital:
Glycosuria, urinary frequency, polyuria, dysuria, hematuria, crystalluria. Other:
Exacerbation of gout
dysfunction, Stevens-Johnson syndrome.
Diagnostic Test Interference
Monitor for false-positive urinary protein determinations; falsely high values for urine urobilinogen; depressed iodine uptake values (exception: hypothyroidism).
Renal excretion of amphetamines
, ephedrine, flecainide, quinidine, procainamide, tricyclic antidepressants
may be decreased, thereby enhancing or prolonging their effects. Renal excretion of lithium
is increased. Excretion of phenobarbital
may be increased. Amphotericin B
may accelerate potassium
loss. digitalis glycosides
may predispose persons with hypokalemia to digitalis
toxicity; puts patients on high doses of salicylates
at high risk for salicylate
Well absorbed from GI tract. Onset:
1 h regular release; 2 h sustained release; 2 min IV. Peak:
24 h reg; 818 h sustained; 15 min IV. Duration:
812 h reg; 1824 h sustained; 45 h IV. Distribution:
Distributed throughout body, concentrating in RBCs, plasma, and kidneys; crosses placenta. Elimination:
Primarily in urine. Half-Life:
Assessment & Drug Effects
- Establish baseline weight before initial therapy and weigh daily thereafter when used to treat edema.
- Monitor for S&S of: mild to severe metabolic acidosis; potassium loss which is greatest early in therapy (see hypokalemia
in Appendix F).
- Monitor I&O especially when used with other diuretics.
- Lab tests: Blood pH, blood gases, urinalysis, CBC, and serum electrolytes (initially and periodically during prolonged therapy
or concomitant therapy with other diuretics or digitalis).
Patient & Family Education
- Maintain adequate fluid intake (1.52.5 L/24 h; 1 liter is approximately equal to 1 quart) to reduce risk of kidney
- Report any of the following: numbness, tingling, burning, drowsiness, and visual problems, sore throat or mouth, unusual
bleeding, fever, skin or renal problems.
- Eat potassium-rich diet and take potassium supplement when taking this drug in high doses or for prolonged periods.