Fomepizole
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From MedlinePlus, U.S. National Library of Medicine
Antidote
Dosing in kidney impairment
Treatment consists of blocking the formation of toxic metabolites using inhibitors of alcohol dehydrogenase, such as fomepizole, and correction of metabolic abnormalities. In patients with high ethylene glycol or methanol concentrations (≥ 50 mg/dL), significant metabolic acidosis, or renal failure, hemodialysis should be considered to remove ethylene glycol or methanol and the respective toxic metabolites of these alcohols.
Hemodialysis: Hemodialysis should be considered in addition to fomepizole in the case of renal failure, significant or worsening metabolic acidosis, or a measured ethylene glycol or methanol concentration of greater than or equal to 50 mg/dL. Patients should be dialyzed to correct metabolic abnormalities and to lower the ethylene glycol concentrations below 50 mg/dL.
All doses should be administered as a slow intravenous infusion over 30 minutes (see Administration ). Dosage with Renal Dialysis: Fomepizole Injection is dialyzable and the frequency of dosing should be increased to every 4 hours during hemodialysis. Fomepizole Dosing in Patients Requiring Hemodialysis [See table below.] DOSING DURING HEMODIALYSIS Dose every 4 hours [See table below.] MAINTENANCE DOSING OFF HEMODIALYSIS Give next scheduled dose 12 hours from last dose administered Administration: Fomepizole solidifies at temperatures less than 25°C (77°F).
| DOSE AT THE BEGINNING OF HEMODIALYSIS | |
| If <6 hours since last fomepizole dose | If ≥ 6 hours since last fomepizole dose |
| Do not administer dose | Administer next scheduled dose |
| DOSING DURING HEMODIALYSIS |
| Dose every 4 hours |
| DOSING AT THE TIME HEMODIALYSIS IS COMPLETED | |
| Time between last dose and the end of hemodialysis | |
| <1 hour | Do not administer dose at the end of hemodialysis |
| 1-3 hours | Administer 1/2 of next scheduled dose |
| >3 hours | Administer next scheduled dose |
| MAINTENANCE DOSING OFF HEMODIALYSIS |
| Give next scheduled dose 12 hours from last dose administered |
Preparation and administration
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DOSAGE AND ADMINISTRATION Do not use polycarbonate syringes or polycarbonate-containing needles (including polycarbonate filter needles) when diluting or administering Fomepizole Injection, 1.5 g/1.5 mL (1 g/mL). Fomepizole can interact with polycarbonate, compromising the integrity of the syringe and/or needle component containing polycarbonate.
If the fomepizole solution has become solid in the vial, the solution should be liquefied by running the vial under warm water or by holding in the hand. Solidification does not affect the efficacy, safety, or stability of fomepizole. Using sterile technique, the appropriate dose of fomepizole should be drawn from the vial with a non-polycarbonate containing syringe and injected into at least 100 mL of sterile 0.9% sodium chloride injection or dextrose 5% injection.
Mix well. The entire contents of the resulting solution should be infused over 30 minutes. Fomepizole, like all parenteral products, should be inspected visually for particulate matter prior to administration. Stability: Fomepizole diluted in 0.9% sodium chloride injection or dextrose 5% injection remains stable and sterile for at least 24 hours when stored refrigerated or at room temperature.
Fomepizole does not contain preservatives. Therefore, maintain sterile conditions, and after dilution do not use beyond 24 hours. Solutions showing haziness, particulate matter, precipitate, discoloration, or leakage should not be used.
Drug interactions
Check fomepizole against a medication listLabel text (1 paragraph)
Drug Interactions: Oral doses of fomepizole (10 to 20 mg/kg), via alcohol dehydrogenase inhibition, significantly reduced the rate of elimination of ethanol (by approximately 40%) given to healthy volunteers in moderate doses. Similarly, ethanol decreased the rate of elimination of fomepizole (by approximately 50%) by the same mechanism. Reciprocal interactions may occur with concomitant use of fomepizole and drugs that increase or inhibit the cytochrome P450 system (e.g., phenytoin, carbamazepine, cimetidine, ketoconazole), though this has not been studied.
Contraindications
Fomepizole should not be administered to patients with a documented serious hypersensitivity reaction to fomepizole or other pyrazoles.
Pregnancy and lactation
Pregnancy
Pregnancy: Pregnancy Category C: Animal reproduction studies have not been conducted with fomepizole. It is also not known whether fomepizole can cause fetal harm when administered to pregnant women or can affect reproduction capacity. Fomepizole should be given to pregnant women only if clearly needed.
Lactation
Nursing Mothers: It is not known whether fomepizole is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised when fomepizole is administered to a nursing woman.
For breastfeeding, also see LactMed (National Library of Medicine), which summarizes milk levels and infant effects.
Supply and cost
Drug shortage status
Recalls (last 24 months)
Therapeutic equivalence (Orange Book)
Price ladder
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