Acetazolamide

DIAMOX

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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

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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.

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

NO BOXED WARNINGS

Principal riskMetabolic acidosis by design; kidney stones

Cost, est. cash$10–$400/month

Generic entry1995

Classes and tags

Clinical profile

Therapeutic safety burden1 / 4

Overdose danger1 / 4

Weight-gain liability0 / 4

Sedation liability0 / 4

QT / Torsades0 / 4

Direct muscarinic antagonism0 / 4

Embryofetal risk1 / 4

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.