Isavuconazole is a triazole antifungal drug. It inhibits fungal sterol biosynthesis by inhibition of cytochrome P450 sterol 14-α-demethylase (CYP51), an enzyme in the sterol biosynthesis pathway that leads from lanosterol to ergosterol. It has been approved for the treatment of both invasive aspergillosis and invasive mucormycosis.