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Generic name: fomepizole [ foe-MEP-i-zole ]
Brand name: Antizol
Dosage form: intravenous solution (1 g/mL)
Drug class: Antidotes

Medically reviewed by on Aug 16, 2023. Written by Cerner Multum.

What is fomepizole?

Fomepizole is an antidote to certain types of poison.

Fomepizole is used to treat poisoning with ethylene glycol (antifreeze) or methanol (contained in solvents, fuels, and other household or automotive chemicals). Fomepizole is sometimes used together with hemodialysis to rid the body of a poison.

Fomepizole may also be used for purposes not listed in this medication guide.

Fomepizole side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Tell your caregiver right away if you have:

  • skin rash, bruising, severe tingling, numbness, pain, muscle weakness.

  • severe nausea, severe dizziness or spinning sensation; or

  • a light-headed feeling, like you might pass out.

Common side effects of fomepizole may include:

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.


In a poisoning situation it may not be possible to tell your caregivers about your health conditions. Make sure any doctor caring for you afterward knows you have received fomepizole.

Before taking this medicine

If possible before you receive fomepizole, tell your doctor if you have:

  • an allergy to any drug;

  • kidney disease or if you are unable to urinate; or

  • if you recently drank alcohol.

FDA pregnancy category C. It is not known whether fomepizole will harm an unborn baby. Tell your doctor if you are pregnant.

It is not known whether fomepizole passes into breast milk or if it could harm a nursing baby. Tell your doctor if you are breast-feeding a baby.

In an emergency situation, it may not be possible before you are treated with fomepizole to tell your caregivers if you are pregnant or breast-feeding. However, make sure any doctor caring for your pregnancy or your baby knows that you have received this medicine.

How is fomepizole given?

Fomepizole is injected into a vein through an IV. A healthcare provider will give you this injection.

You may be given other medicines and IV fluids as part of your treatment.

Your breathing, blood pressure, oxygen levels, kidney function, and other vital signs will be watched closely while you are receiving fomepizole. Your blood and urine will also need to be tested often during treatment, and your heart function may need to be checked using an electrocardiograph or ECG (sometimes called an EKG).

You will also be watched for any effects of the poisoning, such as problems with vision, breathing, or urination.

What happens if I miss a dose?

Because you will receive fomepizole in a clinical setting, you are not likely to miss a dose.

What happens if I overdose?

Since fomepizole is given by a healthcare professional in a medical setting, an overdose is unlikely to occur.

What should I avoid after receiving fomepizole?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What other drugs will affect fomepizole?

Other drugs may interact with fomepizole, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.