Antifungal drug for external use, which has a wide range of antifungal activity. In small concentrations terbinafine has a fungicidal action against dermatophytes (Trichophyton rubrum,
T.mentagrophytes, T.verrucosum, T. violaceum, T.tonsurans, Microsporum canis, Epidermophyton floccosum), molds (for example, Scopulariopsis brevicaulis) and certain dimorphic fungi (Pityrosporum orbiculare). Activity with respect to yeast fungi (mainly Candida albicans), depending on their type, can be fungicidal or fungistatic.
Terbinafine specifically changes the early stage of biosynthesis of sterols occurring in fungi. This leads to a deficit of ergosterol and intracellular accumulation of squalene, which causes death of the fungal cell. The action of terbinafine is carried out by inhibiting the enzyme squalene epoxidase located on the cell membrane of the fungus.
Terbinafine has no effect on the cytochrome P450 isoenzyme system in humans and, accordingly, on the metabolism of hormones or other medications.