<p>Ketoconazole 2% shampoo is a broad spectrum imidazole-dioxolane, synthetic antifungal agent which inhibits the in vitro growth of the following common dermatophytes and yeasts by altering the permeability of the cell membrane: dermatophytes: Trichophyton rubrum, T. mentagrophytes, T. tonsurans, Microsporum canis, M. audouini, M. gypseum and Epidermophyton floc-cosum; yeasts: Candida albicans, Malassezia ovale (Pityrosporum ovale) and C. tropicalis; and the organism responsible for tinea versicolor, Malassezia furfur (Pityrosporum orbiculare).</p>