The three primary routes of voriconazole metabolism are hydroxylation of the fluoropyrimidine ring, hydroxylation of the methyl group, and N-oxidation []. The notation used with regard to the OH group in the “Hydroxylation of the fluoropyrimidine ring” metabolite indicates that the location of the attachment of the OH group is variable – OH is bonded to the ring, but at an unspecified or unknown atom of the ring.