What is the dose range of acetazolamide (carbonic anhydrase inhibitor) for pediatric patients?

Acetazolamide Dosing in Pediatric Patients

For pediatric patients, acetazolamide dosing ranges from 8-30 mg/kg/day divided into multiple doses, with the specific range depending on the indication: 5 mg/kg once daily for diuresis, 8-30 mg/kg/day (optimally 375-1000 mg/day) in divided doses for epilepsy, and 25-100 mg/kg/day for pseudotumor cerebri, with careful titration and monitoring for metabolic acidosis. 1, 2

Indication-Specific Dosing

Epilepsy

• Initial dose: 8-30 mg/kg/day in divided doses 1
• Optimal therapeutic range: 375-1000 mg daily total 1
• When adding to existing anticonvulsants, start with 250 mg once daily and titrate upward 1
• Doses exceeding 1 gram daily generally do not provide additional benefit 1

Glaucoma

• Chronic simple (open-angle) glaucoma: 250 mg to 1 g per 24 hours in divided doses 1
• Doses over 250 mg should be divided throughout the day 1
• Acute/secondary glaucoma: 250 mg every 4 hours, or 500 mg initial dose followed by 125-250 mg every 4 hours 1
• In pediatric glaucoma studies, the average dose used was 9.9 ± 1.8 mg/kg/day 3

Pseudotumor Cerebri (Idiopathic Intracranial Hypertension)

• Initial dose: 25 mg/kg/day, titrated upward until clinical response 2
• Maximum dose: 100 mg/kg/day 2
• In recent pediatric cohorts, the median maximal dose was 18 mg/kg/day 4
• Electrolytes must be monitored for hypokalemia and acidosis 2

Diuresis (Congestive Heart Failure/Drug-Induced Edema)

• Starting dose: 5 mg/kg (250-375 mg) once daily in the morning 1
• Best results achieved with alternate-day dosing or 2 days on/1 day off to allow kidney recovery 1
• Do not increase dose if edema persists; instead skip a day for renal recovery 1

Critical Dosing Considerations

Age-Related Adjustments

• Children and adolescents with ATRA-induced pseudotumor cerebri should receive reduced ATRA doses (25 mg/m² vs 45 mg/m²) to minimize the need for acetazolamide 2
• Younger cardiac patients (median age 0.6 months) may not respond to acetazolamide for metabolic alkalosis as effectively as older noncardiac patients 5

Renal Impairment

• Creatinine clearance <50 mL/min: Do not administer more frequently than every 12 hours 6
• Acetazolamide is primarily eliminated renally and highly protein-bound 6

Metabolic Monitoring

• Metabolic acidosis occurs in 76-90% of pediatric patients on acetazolamide 4
• Laboratory acidosis does not correlate with clinical adverse effects or dose 4
• Blood gas monitoring should be based on clinical judgment rather than routine scheduling 4
• Monitor electrolytes for hypokalemia and acidosis, particularly in pseudotumor cerebri treatment 2

Administration Principles

Dosing Frequency

• Epilepsy and glaucoma require divided doses throughout the day 1
• Diuresis requires intermittent dosing (alternate days or with rest days) for kidney recovery 1
• Plasma half-life is 4-8 hours, but pharmacologic effects last longer 6

Route of Administration

• Oral route is standard for chronic therapy 1
• Intravenous route preferred for acute glaucoma requiring rapid IOP reduction 1
• Intramuscular administration is not recommended 1

Common Pitfalls

Cardiac Patients

• Acetazolamide may not effectively reduce bicarbonate in critically ill children with congenital heart disease post-repair 5
• These patients had unchanged pHCO₃ levels 18 hours after acetazolamide, unlike noncardiac patients who showed significant reduction 5

Formulation Issues

• Acetazolamide suspensions may fail dose uniformity testing despite passing mass content requirements 7
• Use commercially available formulations when possible to ensure consistent dosing 7

Contraindication in Cryptococcal Meningitis

• Do not use acetazolamide for elevated intracranial pressure in cryptococcal meningitis 2
• Associated with excess severe acidosis, hypokalemia, and adverse effects compared to placebo 2