Voriconazole is a triazole antifungal agent. The primary mechanism of action of voriconazole is inhibition of the fungal cytochrome P450-mediated 14α-lanosterol demethylation reaction, which is a key step in fungal ergosterol biosynthesis. Accumulation of 14α-methyl-sterol correlates with subsequent loss of ergosterol from fungal cell membranes and may be responsible for the antifungal activity of voriconazole. Voriconazole has been shown to be more selective for fungal cytochrome P450 enzymes than for cytochrome P450 enzyme systems in various mammals.