Acetazolamide (oral / IV)
Orals / systemic · Rx
Trade namesDiamox, Diamox Sequels
Drug classSystemic carbonic anhydrase inhibitor
Strength125 / 250 mg tablets; 500 mg SR capsule; 500 mg IV
AvailabilityRx
Mechanism of actionSystemic carbonic anhydrase inhibition; a large reduction in aqueous production. Also used for its diuretic / CSF-lowering effects.
Indication / reason for useAcute angle-closure crisis, acute IOP spikes (post-op, uveitic, neovascular), before urgent laser/surgery; idiopathic intracranial hypertension; altitude sickness prophylaxis.
Usual adult dosingAcute: 500 mg IV or PO stat, then 250 mg PO q6h (or 500 mg SR BID). Confirm renal function first.
PreservativeN/A , a preservative-free option exists
Contact lensesNo ocular product; no lens restriction.
Common / important adverse effectsParesthesias (fingers/toes/perioral, near-universal), malaise/fatigue/depression, metallic taste, GI upset, metabolic acidosis, hypokalemia, renal stones, blood dyscrasias (rare), Stevens-Johnson syndrome (rare). Aplastic anemia is a rare idiosyncratic risk.
Contraindications & cautionsSulfonamide hypersensitivity, marked renal or hepatic impairment, hypokalemia/hyponatremia, adrenal insufficiency, hyperchloremic acidosis, sickle cell (can precipitate crisis), first trimester of pregnancy.
Pregnancy / lactationAvoid, especially first trimester (teratogenic in animals; reported limb defects).
Practice notesNot for chronic use if avoidable. Check electrolytes and renal function; caution with high-dose aspirin (salicylate toxicity) and other sulfa drugs.
Chair-side reference only. Dosing, contraindications and pregnancy guidance here are not exhaustive. Confirm against the current prescribing information and the patient’s full history before prescribing or advising.