Acetazolamide
DIAMOX
Pronunciation: a-set-a-ZOEL-a-mide
“A set of migh(ty) Dimes”
Carbonic anhydrase Inhibitor
diuretic
urinary alkalinizer
What it isCarbonic anhydrase inhibitor; glaucoma, altitude illness, raised intracranial pressure, and metabolic alkalosis.
Why this oneDeliberate bicarbonate loss speeds acclimatization while reduced fluid secretion lowers ocular and intracranial pressure.
What limits itMetabolic acidosis, paresthesias, hypokalemia, and kidney stones limit use; sulfonamide reactions can occur.
FDA-approved for
- glaucoma (~1953)
- altitude sickness (~1953)
FDA label
Read the full label on DailyMed ↗
| FDA dosing | Population | Start | Target | Max |
|---|---|---|---|---|
| Chronic open-angle glaucoma (adjunct) | Adult | 250 mg/day | 250 mg–1 g/day in divided doses | 1 g/day (no added effect above) |
| Secondary / acute angle-closure glaucoma (preop) | Adult | 250 mg q4h (or 250 mg BID short-term) | 250 mg q4h; or 500 mg then 125–250 mg q4h | |
| Epilepsy (adjunct) | Adult & pediatric | 250 mg QD added to existing therapy | 8–30 mg/kg/day divided; optimal 375–1000 mg/day | 1 g/day (no added benefit above) |
| Congestive heart failure (diuresis) | Adult | 250–375 mg QD (morning), ~5 mg/kg | 250–375 mg on alternate days / 2-on-1-off | |
| Drug-induced edema | Adult | 250–375 mg QD | 250–375 mg QD alternating with a rest day | |
| Acute mountain sickness | Adult | 500 mg/day divided | 500–1000 mg/day divided | 1000 mg/day (rapid ascent) |
Renal Contraindicated in marked kidney disease/dysfunction
Hepatic Contraindicated in marked liver disease/dysfunction and cirrhosis (hepatic encephalopathy risk)
CHF/edema: give on alternate days or 2-days-on/1-off (skip a day rather than increasing if diuresis plateaus). AMS: start 24–48 h before ascent, continue ~48 h at altitude.
Instructions
- Divide doses above 250 mg.
Available strengths
- tab 125, 250 mg
- ER cap 500 mg
- inj 500 mg
- cap 500 mg
Contraindications
- Depressed serum sodium and/or potassium levels
- Marked kidney disease or dysfunction
- Marked liver disease/dysfunction; cirrhosis (hepatic encephalopathy risk)
- Adrenal (suprarenal) gland failure
- Hyperchloremic acidosis
- Long-term use in chronic noncongestive angle-closure glaucoma
Cautions
- Sulfonamide derivative — cross-sensitivity possible; sulfonamide-type severe reactions (SJS/TEN, blood dyscrasias, fulminant hepatic necrosis) can occur.
- Metabolic acidosis and electrolyte imbalance (hypokalemia, hyponatremia); monitor.
- Transient myopia and choroidal effusion/detachment reported.
- Increased risk of nephrolithiasis/crystalluria with long-term therapy.
Adverse reactions
- Paresthesias (numbness/tingling of extremities and face)
- Taste alteration, loss of appetite, GI upset (nausea/vomiting/diarrhea)
- Metabolic acidosis; hypokalemia, hyponatremia
- Drowsiness, fatigue, dizziness
- Transient myopia
- Rare: blood dyscrasias, SJS/TEN, hepatic necrosis, nephrolithiasis
Pregnancy Teratogenic (limb defects) in animals; no adequate human studies — use only if potential benefit justifies risk.
Lactation Undefined
Cost
Generic entry1995
NO BOXED WARNINGS
Principal riskMetabolic acidosis by design; kidney stones
Classes and tags
Clinical profile
Legacy pregnancy categoryUnknown / historical label unavailable
Defining liabilityGenerally tolerated at therapeutic doses; clinically important risks are agent-specific and increase with interactions or organ impairment.
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