Fomepizole (Antizol) 839 mg in 100 mL 0.9% NaCl IV Infusion
This is the standard dilution and administration method for fomepizole: the medication must be diluted in at least 100 mL of 0.9% sodium chloride (or 5% dextrose) and infused intravenously over 30 minutes 1.
Administration Details
Preparation
- Draw the appropriate dose of fomepizole from the vial using sterile technique
- Inject into at least 100 mL of sterile 0.9% sodium chloride or 5% dextrose
- Mix well before administration 1
Infusion Parameters
- Infusion time: 30 minutes for all doses 1
- The 839 mg dose represents a typical loading or maintenance dose for an adult patient (approximately 15 mg/kg for a 56 kg patient or 10 mg/kg for an 84 kg patient)
Important Preparation Notes
- Fomepizole solidifies at temperatures below 25°C (77°F). If solid, liquefy by running the vial under warm water or holding in hand—this does not affect efficacy, safety, or stability 1
- Inspect visually for particulate matter, haziness, precipitate, discoloration, or leakage before administration 1
- The diluted solution remains stable for 24 hours when refrigerated or at room temperature, but should not be used beyond 24 hours as it contains no preservatives 1
Standard Dosing Context
Loading Dose
- 15 mg/kg IV over 30 minutes 1
Maintenance Dosing (without hemodialysis)
- 10 mg/kg every 12 hours for 4 doses
- Then 15 mg/kg every 12 hours until ethylene glycol or methanol concentrations are undetectable or <20 mg/dL and patient is asymptomatic with normal pH 1
Modified Dosing During Hemodialysis
- Every 4 hours during hemodialysis (due to dialyzability of fomepizole) 1
- For continuous renal replacement therapy (CRRT), a 50% reduced maintenance dose is appropriate, maintaining plasma concentrations above the required 10 µmol/L 2
Clinical Indications
Fomepizole is indicated for ethylene glycol or methanol poisoning when 1:
- Suspected ingestion based on history and/or anion gap metabolic acidosis
- Increased osmolar gap
- Visual disturbances (methanol)
- Oxalate crystals in urine (ethylene glycol)
- Documented serum concentration >20 mg/dL
Key Safety Points
- Few serious adverse effects reported; most common are headache, dizziness, vomiting, and unpleasant taste 3, 4
- Local pain at injection site may occur 5
- No need to monitor fomepizole concentrations during treatment 6
- Contraindicated in patients with allergy to pyrazoles 6
The 839 mg dose in 100 mL represents proper pharmaceutical preparation following FDA-approved guidelines for safe intravenous administration of this alcohol dehydrogenase inhibitor.