Intravenous Acetazolamide: Indications and Dosing Guidelines
Intravenous acetazolamide should be administered via the direct intravenous route with specific dosing based on indication, with glaucoma requiring 250 mg to 1 g daily (divided for doses over 250 mg), epilepsy requiring 8-30 mg/kg daily in divided doses, and congestive heart failure requiring 250-375 mg (5 mg/kg) once daily in the morning. 1
Preparation and Administration
- Each 500 mg vial of acetazolamide for injection should be reconstituted with at least 5 mL of Sterile Water for Injection prior to use 1
- Reconstituted solutions remain stable for 3 days under refrigeration (2-8°C) or 12 hours at room temperature (20-25°C) 1
- The direct intravenous route is preferred; intramuscular administration is not recommended 1
- Contains no preservative, requiring careful handling to maintain sterility 1
Indications and Dosing
Glaucoma
- Dosage for chronic simple (open-angle) glaucoma: 250 mg to 1 g per 24 hours, usually in divided doses for amounts over 250 mg 1
- For secondary glaucoma and preoperative treatment of acute congestive (closed-angle) glaucoma: 250 mg every four hours (some cases respond to 250 mg twice daily) 1
- For acute cases: Initial dose of 500 mg followed by 125-250 mg every four hours 1
- IV therapy provides rapid relief of ocular tension in acute cases 1
- Dosages exceeding 1 g per 24 hours typically do not produce increased effect 1
Epilepsy
- Total daily dose: 8-30 mg/kg in divided doses 1
- Optimum range: 375-1000 mg daily 1
- When used with other anticonvulsants: Start with 250 mg once daily, then increase as needed 1
- Best results seen in petit mal epilepsy in pediatric patients, though effective for other seizure types 1
Congestive Heart Failure (Diuresis)
- Starting dose: 250-375 mg (5 mg/kg) once daily in the morning 1
- For optimal diuretic effect: Administer on alternate days or for two days alternating with a day of rest 1
- If patient stops responding, skip medication for a day to allow kidney recovery rather than increasing the dose 1
Drug-Induced Edema
- Recommended dosage: 250-375 mg once daily for one or two days, alternating with a day of rest 1
Other Off-Label Uses
- Idiopathic intracranial hypertension and elevated intracranial pressure due to CSF leaks 2
- Ventilator weaning for COPD patients 2
- Prevention of high-dose methotrexate toxicity and contrast-induced nephropathy 2
- Acute mountain sickness (though typically oral administration is used) 3, 4, 5
Special Considerations
- For patients with renal impairment: Administration should not be more frequent than every 12 hours if creatinine clearance is less than 50 mL/min 2
- Acetazolamide should not be used orally to reduce intracranial pressure in cryptococcal meningitis (DIII recommendation) 6
- Acetazolamide may be used as part of a synergistic diuretic regimen for resistant edema in nephrotic syndrome 6
Monitoring and Side Effects
- Common side effects include paraesthesias, taste disturbances, polyuria, and fatigue 7
- Side effects appear to be dose-dependent, with higher risks at higher doses 7
- Monitor for metabolic acidosis, electrolyte imbalances, and kidney function 2
- May interfere with laboratory tests including urinary phenolsulfonphthalein, phenol red elimination, urinary protein, serum non-protein, serum uric acid, and theophylline assays 1
Contraindications
- Hypersensitivity to sulfonamides 1
- Severe hepatic or renal dysfunction 1
- Adrenocortical insufficiency 1
- Hyperchloremic acidosis 1
By following these guidelines for IV acetazolamide administration, clinicians can appropriately utilize this medication for its various indications while minimizing risks to patients.