4-methylpyrazole
4-methylpyrazole Uses, Dosage, Side Effects, Food Interaction and all others data.
4-methylpyrazole is used as an antidote in confirmed or suspected methanol or ethylene glycol poisoning. 4-methylpyrazole is a competitive inhibitor of alcohol dehydrogenase, the enzyme that catalyzes the initial steps in the metabolism of ethylene glycol and methanol to their toxic metabolites.
4-methylpyrazole is a competitive inhibitor of alcohol dehydrogenase, the enzyme that catalyzes the initial steps in the metabolism of ethylene glycol and methanol to their toxic metabolites. Ethylene glycol is first metabolized to glycoaldehyde which then undergoes further oxidation to glycolate, glyoxylate, and oxalate. Glycolate and oxalate are primarily responsible for metabolic acidosis and renal damage seen in ethylene glycol toxicity. {01}{03} Methanol is first metabolized to formaldehyde and then undergoes subsequent oxidation via formaldehyde dehydrogenase to become formic acid. It is formic acid that is primarily responsible for the metabolic acidosis and visual disturbances that are associated with methanol poisoning.
| Trade Name | 4-methylpyrazole |
| Availability | Prescription only |
| Generic | Fomepizole |
| Fomepizole Other Names | 4-methylpyrazol, 4-methylpyrazole, Fomepizol, Fomepizole, Fomepizolum |
| Type | |
| Formula | C4H6N2 |
| Weight | Average: 82.1038 Monoisotopic: 82.053098202 |
| Groups | Approved, Vet approved |
| Therapeutic Class | |
| Manufacturer | |
| Available Country | |
| Last Updated: | September 19, 2023 at 7:00 am |
Uses
4-methylpyrazole is an inhibitor of alcohol dehydrogenase used as an antidote in confirmed or suspected methanol or ethylene glycol poisoning.
Antizol is indicated as an antidote for ethylene glycol (such as antifreeze) or methanol poisoning, or for use in suspected ethylene glycol or methanol ingestion, either alone or in combination with hemodialysis
4-methylpyrazole is also used to associated treatment for these conditions: Ethylene glycol poisoning, Methanol poisoning
How 4-methylpyrazole works
Antizol (fomepizole) is a competitive inhibitor of alcohol dehydrogenase. Alcohol dehydrogenase catalyzes the oxidation of ethanol to acetaldehyde. Alcohol dehydrogenase also catalyzes the initial steps in the metabolism of ethylene glycol and methanol to their toxic metabolites.
Toxicity
Headache, nausea, dizziness
Food Interaction
- Avoid alcohol. 4-methylpyrazole reduces the metabolism of alcohol by alcohol dehydrogenase, and alcohol also reduces fomepizole metabolism and elimination.
4-methylpyrazole Alcohol interaction
[Major] GENERALLY AVOID:
The manufacturer reports that oral doses of fomepizole (10 to 20 mg/kg) will significantly reduce the rate of elimination of moderate doses of ethanol by approximately 40% when given to healthy volunteers.
The mechanism is via alcohol dehydrogenase inhibition.
By a similar mechanism, ethanol will decrease the rate of elimination of fomepizole.
In general, ethanol and fomepizole should not be coadministered in the treatment of ethylene glycol poisoning.
4-methylpyrazole Disease Interaction
Volume of Distribution
- 0.6 to 1.02 L/kg
Elimination Route
Rapid and complete
Half Life
The plasma half-life of Antizol varies with dose, even in patients with normal renal function, and has not been calculated.
Elimination Route
In healthy volunteers, only 1-3.5% of the administered dose of Antizol® (7-20 mg/kg oral and IV) was excreted unchanged in the urine, indicating that metabolism is the major route of elimination. In humans, the primary metabolite of Antizol® is 4-carboxypyrazole (approximately 80-85% of administered dose), which is excreted in the urine. The metabolites of Antizol® are excreted renally.
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