Butenafine

Butenafine is a new antifungal agent with primary fungicidal activity against dermatophytes such as Trichophyton mentagrophytes, Microsporum canis and Trichophyton rubrum which cause tinea infections. 14C-labelled butenafine (approximately 30 micrograms/g tissue) was found within guinea-pig dorsal skin 24 hours after topical application. Most of the drug was distributed into the epidermis including the horny layer. Small amounts were found in the dermis, probably transported via sebaceous glands and hair follicles. In vitro, the minimum concentration that completely inhibited growth of dermatophytes (MIC) and the minimum fungicidal concentrations (MFC) for butenafine against T. mentagrophytes and M. canis were similar (0.012 to 0.05 mg/L) and were 4 to 130 times lower than those for naftifine, tolnaftate, clotrimazole and bifonazole. It also has greater activity against T. rubrum, M. gypseum and Epidermophyton floccosum when compared with naftifine, tolnaftate and clotrimazole; comparisons with bifonazole against these strains were not available. Assessment after 1 week's treatment in patients with tinea pedis revealed that mycological cure rates were greater in those who received twice-daily butenafine for 1 week or once-daily butenafine for 4 weeks than in placebo recipients. Mycological and overall cure rates were either further increased or maintained up to 5 weeks after treatment cessation compared with end-of-treatment values. In patients with tinea cruris or tinea corporis who received once-daily butenafine 1% for 2 weeks, the mycological and overall cure rates continued to increase for up to 4 weeks after treatment cessation.