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.