Products
Fomepizole is commercially available as an injection or infusion solution. In many countries, the drug is not registered, but it is among the official antidotes of the FOPH and can be imported from abroad.
Structure and properties
Fomepizole (C4H6N2, Mr = 82.1 g/mol) is 4-methylpyrazole, a clear to yellow liquid that can exist as a solid at room temperature (melting point at 25°C). Fomepizole is soluble in water.
Effects
Fomepizole (ATC V03AB34) is a competitive inhibitor of alcohol dehydrogenase. This enzyme catalyzes the oxidation of ethanol to acetaldehyde. Alcohol dehydrogenase forms the toxic metabolites from ethylene glycol. Inhibition of the enzyme causes ethylene glycol to be excreted unchanged by the kidneys.
Indications
For the treatment of poisoning with ethylene glycol, a commonly used antifreeze. Fomepizole is also used to treat methanol poisoning.
Dosage
According to the professional information leaflet.
Contraindications
Fomepizole is contraindicated in case of hypersensitivity. For complete precautions, see the drug label.
Interactions
Fomepizole should not be administered concomitantly with ethanol (alcohol). It is an inhibitor and inducer of CYP450.
Adverse effects
Possible adverse effects include changes in heart rate, hypertension, dizziness, convulsions, visual disturbances, speech disorders, anxiety, restlessness, digestive problems, and injection site reactions.
