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Antizol Side Effects

Generic Name: fomepizole

Note: This page contains information about the side effects of fomepizole. Some of the dosage forms included on this document may not apply to the brand name Antizol.

Not all side effects for Antizol may be reported. You should always consult a doctor or healthcare professional for medical advice. Side effects can be reported to the FDA here.

For the Consumer

Applies to fomepizole: parenteral injection concentrate for iv infusion

Side effects include:

Headache, nausea, dizziness, increased drowsiness, bad/metallic taste.

For Healthcare Professionals

Applies to fomepizole: intravenous solution


Hematologic side effects have included eosinophilia/hypereosinophilia, lymphangitis, disseminated intravascular coagulation, and anemia.[Ref]


In one case report, transient bradycardia (50 to 60 beats per minute) occurred in a 35-year-old man 2.5 hours after receiving his first dose of fomepizole (the active ingredient contained in Antizol) Another case was reported in a 20-year-old man 16 hours after his last dose of fomepizole.[Ref]

Cardiovascular side effects have included sinus bradycardia, tachycardia, phlebosclerosis, phlebitis, shock, and hypotension.[Ref]


Gastrointestinal side effects have included nausea, vomiting, diarrhea, abdominal pain, dyspepsia, heartburn, decreased appetite, abdominal pain, and unpleasant taste.[Ref]

Nervous system

A case report of a 57-year-old man experienced a generalized seizure during a myocardial infarction that had begun prior to admission to the hospital. The seizure started 15 minutes after the first dose of fomepizole (the active ingredient contained in Antizol) In another case, a 33-year-old man had a seizure 15 minutes after the administration of the first dose of fomepizole. The seizure reported lasted 45 to 60 seconds.[Ref]

Nervous system side effects have included headache (14%), dizziness (6%), and increased drowsiness (6%). Other, less common nervous system effects (3% or less) have included facial flush, seizure, nystagmus, anxiety, agitation, lightheadedness, and vertigo.[Ref]


Musculoskeletal side effects have included lumbalgia and backache.[Ref]


Respiratory side effects have included pharyngitis and hiccups.[Ref]


Genitourinary side effects have included anuria.[Ref]


Other side effects have included fever, multiorgan system failure, abnormal smell, speech disturbances, and roar in ear.[Ref]


Hepatic side effects have included transient transaminitis.[Ref]


Ocular side effects have included visual disturbances and blurred vision.[Ref]


Dermatologic side effects have included rash and application site reaction.[Ref]


Local side effects have included injection pain and injection site inflammation.[Ref]


1. Brent J, McMartin K, Phillips S, et al. "Fomepizole for the treatment of ethylene glycol poisoning. Methylpyrazole for Toxic Alcohols Study Group." N Engl J Med 340 (1999): 832-8

2. "Product Information. Antizol (fomepizole)." Orphan Medical, Minnetonka, MN.

3. Lepik KJ, Levy AR, Sobolev BG, et al. "Adverse drug events associated with the antidotes for methanol and ethylene glycol poisoning: a comparison of ethanol and fomepizole." Ann Emerg Med 53 (2008): 439-50.e10.

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