Butenafine

Teratogenic Effects

Subcutaneous doses of butenafine (dose levels up to 25 mg/kg/day administered during organogenesis) (equivalent to 0.5 times the maximum recommended dose in humans for tinea versicolor based on body surface area comparisons) were not teratogenic in rats. In an oral embryofetal development study in rabbits (dose levels up to 400 mg butenafine HCl/kg/day administered during organogenesis) (equivalent to 16 times the maximum recommended dose in humans for tinea versicolor based on body surface area comparisons), no treatment-related external, visceral, skeletal malformations or variations were observed.

In an oral peri- and post-natal developmental study in rats (dose levels up to 125 mg butenafine HCl/kg/day) (equivalent to 2.5 times the maximum recommended dose in humans for tinea versicolor based on body surface area comparisons), no treatment-related effects on postnatal survival, development of the F1 generation or their subsequent maturation and fertility were observed.

There are, however, no adequate and well-controlled studies that have been conducted with topically applied butenafine in pregnant women. Because animal reproduction studies are not always predictive of human response, this drug should be used during pregnancy only if clearly needed.

It is not known if butenafine HCl is excreted in human milk. Because many drugs are excreted in human milk, caution should be exercised in prescribing butenafine cream to a nursing woman.

Long-term studies to evaluate the carcinogenic potential of Mentax Cream, 1%, have not been conducted. Two in vitro assays (bacterial reverse mutation test and chromosome aberration test in Chinese hamster lymphocytes) and one in vivo study (rat micronucleus bioassay) revealed no mutagenic or clastogenic potential for butenafine.

In subcutaneous fertility studies conducted in rats at dose levels up to 25 mg/kg/day (0.5 times the maximum recommended dose in humans for tinea versicolor based on body surface area comparisons), butenafine did not produce any adverse effects on male or female fertility.

In controlled clinical trials, 9 (approximately 1%) of 815 patients treated with butenafine cream, 1%, reported adverse events related to the skin. These included burning/stinging, itching and worsening of the condition. No patient treated with butenafine cream, 1%, discontinued treatment due to an adverse event. In the vehicle-treated patients, 2 of 718 patients discontinued because of treatment site adverse events, one of which was severe burning/stinging and itching at the site of application.

In uncontrolled clinical trials, the most frequently reported adverse events in patients treated with butenafine cream, 1%, were: contact dermatitis, erythema, irritation, and itching, each occurring in less than 2% of patients.

In provocative testing in over 200 subjects, there was no evidence of allergic-contact sensitization for either cream or vehicle base for butenafine cream, 1%.