Acetazolamide
General
- Type: Carbonic anhydrase inhibitor
- Dosage Forms: PO/IV
- Common Trade Names: Diamox
Adult Dosing
Glaucoma
- Closed-angle Glaucoma:
- 500mg PO/IV, followed by 125-250mg PO q4h
- 500mg PO q12h (sustained release)
- Open-angle Glucoma:
- 250mg-1g PO/IV QD
- 500mg PO q12h (sustained release)
Acute altitude sickness
Treatment
- 500-1000mg extended release PO QD
- Continue treatment for 48 hours or longer if necessary
Prophylaxis
- 125mg PO BID[1]
- Start 24hr before ascent and continue for the first 48hrs at peak altitude
CHF-associated Edema
- 250-375mg PO qAM
- 5mg/kg
Drug-induced Edema
- 250-375mg PO qAM
Epilepsy
- 8-30mg/kg/day PO QD
- Do not exceed 30mg/kg/day or 1g/day
Off-label use
- Familial periodic paralysis; Hydrocephalus, normal-pressure; Idiopathic intracranial hypertension; Metabolic alkalosis; Prevention of cystine renal calculi (adjunctive therapy); Respiratory stimulant in stable hypercapnic COPD
Pediatric Dosing
Epilepsy
- <12 years: safety and efficacy not established
- >12 years: 8-30mg/kg/day PO QD
Acute altitude sickness
Treatment
- <12 years: safety and efficacy not established
- >12 years: 500-1000mg PO QD
Prophylaxis
- 2.5mg/kg/dose (maximum 125mg/dose) PO every 12 hours[2]
- Start 24hr before ascent and continue for the first 48hrs at peak altitude
Special Populations
- Pregnancy Rating: C
- Lactation risk: Safe
- Renal Dosing
- Adult: CrCl 10-50: give q12h; CrCl<10: avoid use; HD/PD: not defined
- Pediatric: CrCl 10-50: give q12h; CrCl<10: avoid use, HD/PD: not defined
- Hepatic Dosing
- Adult: contraindicated in significant impairment/cirrhosis
- Pediatric: contraindicated in significant impairment/cirrhosis
- Geriatric: Refer to adult dosing. Oral: Initial doses should begin at the low end of the dosage range.
Contraindications
- Allergy to class/drug
- hypokalemia
- hyponatremia
- acidosis, hyperchloremic
- acidosis, metabolic
- adrenal insufficiency
- cirrhosis
- hepatic disease, severe
- renal disease, severe
- glaucoma, angle-closure (long-term use)
- caution if hypersensitivity to sulfonamides
- caution if ASA treatment, high-dose
- caution if hepatic impairment
- caution if pulmonary impairment
- caution if diabetes mellitus
- caution if gout
- caution if elderly patients
Adverse Reactions
Serious
- metabolic acidosis
- electrolyte imbalance
- anaphylaxis
- erythema multiforme
- Stevens-Johnson syndrome
- toxic epidermal necrolysis
- hepatic necrosis
- hepatic impairment
- agranulocytosis
- anemia, hemolytic
- myelosuppression
- leukopenia
- pancytopenia
- blood dyscrasias
- thrombocytopenic purpura
- seizures
- paralysis, flaccid
- crystalluria
- nephrolithiasis
Common
- fatigue
- malaise
- taste change
- anorexia
- nausea/vomiting
- parethesia
- diarrhea
- polyuria
- electrolyte disorders
- tinnitus
- hearing changes
- myopia
- drowsiness
- confusion
- uticaria
- rash
- photosensitivity
- glucosuria
- hematuria
- melena
Pharmacology
- Half-life: 10-15h
- Metabolism: CYP450
- Excretion: urine (100% unchanged)
- Mechanism of Action: inhibits carbonic anhydrase
Comments
See Also
References
- ↑ Luks AM, McIntosh SE, Grissom CK, et al. Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2014 Update. Wilderness & Environmental Medicine. 2014(25): S4–S14)
- ↑ Luks AM, McIntosh SE, Grissom CK, et al. Wilderness Medical Society Practice Guidelines for the Prevention and Treatment of Acute Altitude Illness: 2014 Update. Wilderness & Environmental Medicine. 2014(25): S4–S14)
- Acetazolamide injection [prescribing information]. Big Flats, NY: X-Gen Pharmaceuticals, Inc; October 2015.