Selenium Sulfide

Topical selenium sulfide may act by an antimitotic action, resulting in a reduction in the turnover of epidermal cells. It also has local irritant, antibacterial, and mild antifungal activity, which may contribute to its effectiveness. An antimitotic mechanism of action is suggested by data showing that selenium sulfide decreases the rate of incorporation of radioactively labeled thymidine into the DNA of dermal epithelial cells. The following organisms are generally considered susceptible to selenium sulfide in vitro: Malassezia furfur, Microsporum sp. including Microsporum audouinii and Microsporum canis, Pityrosporon sp., Trichophyton sp. including Trichophyton schoenleinii and Trichophyton tonsurans. Selenium sulfide has been shown to be sporicidal to T. tonsurans, the most common etiologic agent of tinea capitis. One in-vitro study demonstrated that 2.5% selenium sulfide was equivalent in sporicidal activity to both 1% and 2% zinc pyrithione.