Fomepizole (4-Methylpyrazole)

Fomepizole (4-Methylpyrazole): Uses, Dosage and Side Effects

Overview

• Competitive inhibition of alcohol dehydrogenase.

Uses of Fomepizole (4-Methylpyrazole)

• Treatment of ethylene glycol (antifreeze) toxicity in dogs.

Dose of Fomepizole (4-Methylpyrazole) in Dogs and Cats

Dogs:

• Ethylene glycol toxicity: 20 mg/kg i.v. infusion over 30 min initially, then 15 mg/kg i.v. slowly over 15–30 min 12 h and 24 h later, then 5 mg/kg i.v. q12h until ethylene glycol concentration is negligible or the dog has recovered.
• Most effective if started within 8 hours of intoxication.

Cats:

• Ethylene glycol toxicity: 125 mg/kg slow i.v. then 31.25 mg/kg i.v. q12h for 3 additional doses.
• Efficacy has been shown if treated within 3 hours of ingestion.

Side Effects of Fomepizole (4-Methylpyrazole) in Dogs and Cats

• No information is available.

Contraindications of Fomepizole (4-Methylpyrazole) in Dogs and Cats

• No information is available.

Some Notes:

• Increases risk of ethanol toxicity if co-administered.