fomepizole

REMS

Antidote for ethylene glycol (antifreeze) or methanol (windshield washer fluid) poisoning, alone or with hemodialysis (for ethylene glycol or methanol levels ≥50 mg/dL, renal failure or significant metabolic acidosis).

Contraind./Precautions ⬆ ⬇

Contraindicated in:

Hypersensitivity to fomepizole or other pyrazoles.

Use Cautiously in:

OB: Use during pregnancy only if potential maternal benefit justifies potential fetal risk;
Lactation: Use while breastfeeding only if potential maternal benefit justifies potential risk to infant;
Pedi: Safety and effectiveness not established in children;
Geri: Safety and effectiveness not established in older adults.

Adv. Reactions/Side Effects ⬆ ⬇

GI: nausea

Neuro: headache, dizziness, drowsiness, dysgeusia

Misc: allergic reactions (mild rash, eosinophilia)

Interactions ⬆ ⬇

Drug-drug:

None reported.

Availability ⬆ ⬇

(Generic available)

Solution for injection: 1 g/mL

Route/Dosage ⬆ ⬇

IV (Adults ): Loading dose: 15 mg/kg, then 10 mg/kg every 12 hours for four doses, then 15 mg/kg every 12 hours until levels of methanol or ethylene glycol are undetectable or <20 mg/dL and patient is asymptomatic with normal pH.Patients requiring hemodialysis (beginning): wait at least 6 hr after initiating hemodialysis to give next scheduled dose; during hemodialysis: give dose every 4 hr; when hemodialysis is completed: if time between last dose and end of dialysis is <1 hr, do not administer dose at the end of hemodialysis, if time between last dose and end of hemodialysis is 1–3 hr give 1/2 of next scheduled dose, if time between last dose and end of hemodialysis is >3 hr give next scheduled dose, Treatment is continued until levels of methanol or ethylene glycol are undetectable or <20 mg/dL and patient is asymptomatic with normal pH.

Action ⬆ ⬇

Inhibits initial metabolism of ethylene glycol or methanol to toxic metabolites.

Therapeutic effects:

Decreased morbidity and mortality in ethylene glycol and methanol poisoning.

Classifications ⬆ ⬇

Therapeutic Classification: antidotes

Pharmacologic Classification: enzyme inhibitors

Pharmacokinetics ⬆ ⬇

Absorption: IV administration results in complete bioavailability.

Distribution: Distributes to total body water.

Metabolism/Excretion: Mostly metabolized, less than 1–3.5% excreted unchanged in urine.

Half-Life: Unknown

Canadian Brand Names ⬆ ⬇

Time/Action Profile ⬆ ⬇

ROUTE	ONSET	PEAK	DURATION
IV	rapid	end of infusion	12 hr

Patient/Family Teaching ⬆ ⬇

Explain purpose of fomepizole to patient.
Advise patient to notify health care professional if signs and symptoms of allergic reaction occur.
Advise patient to notify health care professional if pregnancy is planned or suspected or if breastfeeding.

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Indications ⬇