What is Fomepizole: Uses, Warnings & Interactions

Updated May 14, 2025  •  Published Sep 24, 2021

Fomepizole overview

BRAND NAMES:

Generic Names:

  • Fomepizole

Uses:

  • Treats accidental poisoning caused by ethylene glycol (anti-freeze) or methanol.

Therapeutic Classes:

  • Antidote

Forms:

  • Injectable

How it’s taken:

  • By injection

What is Fomepizole used for?

What form(s) does Fomepizole come in

  • Injectable

What are common Fomepizole doses?

  • Vial 1.5ML of 1.5GM/1.5ML

Common Fomepizole prescriptions

  • Fomepizole
    1.5ml of 1.5gm/1.5ml vial

How to take Fomepizole

  • Injection routeYour doctor will prescribe your dose and schedule. This medicine is given through a needle placed in a vein.

  • Injection routeA nurse or other health provider will give you this medicine.

What to do if you miss a dose of Fomepizole

Fomepizole contraindications

  • You should not receive this medicine if you have had an allergic reaction to fomepizole.

Fomepizole warnings

  • Make sure your doctor knows if you are pregnant or breast feeding.

  • Your doctor will do lab tests at regular visits to check on the effects of this medicine. Keep all appointments.

  • This medicine may make you dizzy or drowsy. Avoid driving, using machines, or doing anything else that could be dangerous if you are not alert.

  • Fever, sore throat.

  • Lightheadedness or fainting.

  • Pain, redness, itching, swelling, blistering, or rash where the needle is placed.

  • Speech problems, or inability to stand or walk.

  • Seizure.

  • Severe nausea, vomiting, or diarrhea.

  • Unusual bleeding, bruising, or weakness.

Fomepizole interactions

  • Make sure your doctor knows if you are using medicine for seizure such as phenytoin (Dilantin®) or carbamazepine (Tegretol®). Tell your doctor if you use stomach medicine such as cimetidine (Tagamet®), or medicine for fungal infection such as ketoconazole (Nizoral®).

  • Do not drink alcohol while you are using this medicine.

  • This medicine may make you dizzy or drowsy. Avoid driving, using machines, or doing anything else that could be dangerous if you are not alert.

Fomepizole side effects

Serious Side Effects

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing

  • Decrease in how much or how often you urinate.

  • Fast or slow heartbeat.

  • Fever, sore throat.

  • Lightheadedness or fainting.

  • Pain, redness, itching, swelling, blistering, or rash where the needle is placed.

  • Speech problems, or inability to stand or walk.

  • Seizure.

  • Severe nausea, vomiting, or diarrhea.

  • Unusual bleeding, bruising, or weakness.

Less Serious Side Effects

  • Blurred vision, headache, or ringing in your ears.

  • Mild nausea, vomiting, diarrhea, loss of appetite, hiccups, or bad or metallic taste in your mouth.

  • Mild skin rash or itching.

  • Trouble sleeping.

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