Terbinafine, a synthetic allylamine antifungal, inhibits ergosterol synthesis by inhibiting squalene epoxidase, an enzyme that is part of the fungal cell membrane synthesis pathway.
Butenafine hydrochloride is a hydrochloride of butenafine, which inhibits squalene epoxidase to inhibit the synthesis of ergosterol, leading to the increased permeability of the cell membranes, allowing their contents to leak out.