====== Acetazolamide (Diamox®) ======
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|^ Acetazolamide || Brand Names | Diamox® || Drug Class | Carbonic Anhydrase Inhibitor || Primary Indications | Glaucoma; Altitude sickness; Metabolic alkalosis; Idiopathic intracranial hypertension || Blood Pressure Effect | Mild ↓ BP || Mortality Benefit | No || Elimination | Renal || Black Box Warning | No || FDA Approval | 1954 |
===== Overview =====Acetazolamide is a carbonic anhydrase inhibitor that reduces proximal bicarbonate reabsorption, producing a mild diuresis and metabolic acidosis. It is used for glaucoma, altitude sickness, metabolic alkalosis, and to reduce CSF/aqueous production.
—-===== Mechanism of Action =====Primary Molecular Target * Carbonic anhydrase (proximal tubule)Segment Effects * ↓ HCO3− reabsorption in proximal tubule * ↑ NaHCO3 and water excretion * Mild natriuresisNet Physiologic Outcomes * Mild diuresis * Metabolic acidosis * ↓ Aqueous humor and CSF production—-===== Indications ===== * Glaucoma (↓ aqueous humor) * Altitude sickness prophylaxis/treatment * Metabolic alkalosis * Idiopathic intracranial hypertension * Periodic paralysis (selected cases)—-
===== Black Box Warning =====No black box warning.
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===== Contraindications =====Absolute: * Sulfonamide allergy (severe) * Severe hepatic disease (risk of encephalopathy)Relative / Caution: * Hyponatremia * Hypokalemia * Renal impairment * COPD (risk of acidosis)
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===== Dosing =====Typical dosing varies by indication: * Glaucoma: 250–1000 mg/day divided * Altitude sickness: 125–250 mg BID * IIH: 500–1000 mg/day (titrate)Renal adjustment: * Required in reduced eGFR
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===== Pharmacokinetics =====Absorption: * OralBioavailability: * ~90%Metabolism: * MinimalHalf-life: * ~10–15 hoursElimination: * Renal (unchanged)
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===== Adverse Effects =====Common: * Paresthesias * Polyuria * Metallic taste * FatigueSerious: * Metabolic acidosis * Nephrolithiasis * Hypokalemia * Sulfa reactions
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===== Drug Interactions =====Increased risk: * Other diuretics (electrolyte loss) * Salicylates (toxicity risk)Avoid combination: * High-dose aspirin in severe renal/hepatic disease
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===== Monitoring =====Labs: * Bicarbonate * Electrolytes (K+, Na+) * CreatinineVitals: * Blood pressureClinical: * Symptoms of acidosis * Paresthesias
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===== Clinical Pearls ===== * Weak diuretic but powerful for glaucoma/altitude * Causes a non–anion gap metabolic acidosis * Can cause kidney stones (alkaline urine)
—-===== Comparison Within Class =====Compared to other carbonic anhydrase inhibitors: * Shorter BP effect than thiazides/loops * Unique use in altitude sickness/IIH * Most commonly used CAI diuretic—-===== Related ===== * Carbonic Anhydrase Inhibitors * Diuretics * Cardiovascular Pharmacology