4-Hydroxymethylpyrazole is the primary metabolite of Fomepizole . Fomepizole is a competitive inhibitor of the enzyme alcohol dehydrogenase[1].
[1]. R Blomstrand, et al. Pyrazoles as Inhibitors of Alcohol Oxidation and as Important Tools in Alcohol Research: An Approach to Therapy Against Methanol Poisoning. Proc Natl Acad Sci U S A . 1979 Jul;76(7):3499-503.