Title: Fomepizole
CAS Registry Number: 7554-65-6
CAS Name: 4-Methyl-1H-pyrazole
Additional Names: 4-MP
Trademarks: Antizol (Orphan Med.)
Molecular Formula: C4H6N2
Molecular Weight: 82.10
Percent Composition: C 58.52%, H 7.37%, N 34.12%
Literature References: Alcohol dehydrogenase inhibitor. Prepn: H. Pechmann, E. Burkard, Ber. 33, 3590 (1900); D. S. Noyce et al., J. Org. Chem. 20, 1681 (1955); T. Momose et al., Heterocycles 30, 789 (1990). Inhibition of human liver alcohol dehydrogenase: T.-K. Li, H. Theorell, Acta Chem. Scand. 23, 892 (1969). Toxicity study: G. Magnusson et al., Experientia 28, 1198 (1972). GC determn in plasma and urine: R. Achari, M. Mayersohn, J. Pharm. Sci. 73, 690 (1984). Clinical pharmacology: D. Jacobsen et al., Alcohol. Clin. Exp. Res. 12, 516 (1988). Pharmacokinetics: eidem, Eur. J. Clin. Pharmacol. 37, 599 (1989). Clinical trial in ethylene glycol poisoning: J. Brent et al., N. Engl. J. Med. 340, 832 (1999); in methanol poisoning: idem et al., ibid. 344, 424 (2001). Review: J. Likforman et al., J. Toxicol. Clin. Exp. 7, 373-382 (1987). Review of use in methanol poisoning: M. B. Mycyk, J. B. Leikin, Am. J. Therapeut. 10, 68-70 (2003).
Properties: mp 15.5-18.5°. bp18mm 98.5-99.5°; bp730 204-205°. nD22 1.4913. uv max in 95% ethanol: 220 nm (log e 3.47); in 6N HCl: 226 nm (log e 3.65). Sol in water, alcohol. LD50 (7 days) in mice, rats (mmol/kg): 3.8, 3.8 i.v.; 7.8, 6.5 orally (Magnusson).
Melting point: mp 15.5-18.5°
Boiling point: bp18mm 98.5-99.5°; bp730 204-205°
Index of refraction: nD22 1.4913
Absorption maximum: uv max in 95% ethanol: 220 nm (log e 3.47); in 6N HCl: 226 nm (log e 3.65)
Toxicity data: LD50 (7 days) in mice, rats (mmol/kg): 3.8, 3.8 i.v.; 7.8, 6.5 orally (Magnusson)
Therap-Cat: Antidote to methanol and ethylene glycol poisoning.
Therap-Cat-Vet: Antidote to ethylene glycol poisoning in dogs.
Keywords: Antidote (Methanol and Ethylene Glycol Poisoning).
Fomesafen Fominoben Fomocaine Fonazine Fondaparinux Sodium

Chemical structure of Fomepizole
CAS number 7554-65-6 YesY
PubChem 3406
ChemSpider 3289 YesY
DrugBank DB01213
KEGG D00707 YesY
ATC code V03AB34
Jmol-3D images Image 1
Molecular formula C4H6N2
Molar mass 82.10 g mol−1
Density 0.99 g/cm3
Boiling point 204-207 °C (97,3 kPa)
Flash point 96.0 °C; 204.8 °F; 369.1 K
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C (77 °F), 100 kPa)
Infobox references

Fomepizole or 4-methylpyrazole is indicated for use as an antidote in confirmed or suspected methanol[1] or ethylene glycol[2] poisoning. It may be used alone or in combination with hemodialysis. Apart from medical uses, the role of 4-methylpyrazole in coordination chemistry has been studied.[3]