Mentax Information
Mentax (Butenafine hydrochloride) Description
Mentax (Butenafine hydrochloride) Cream, 1%, contains the synthetic antifungal agent, butenafine hydrochloride. Butenafine is a member of the class of antifungal compounds known as benzylamines which are structurally related to the allylamines.
Butenafine HCl is designated chemically as N-4--butylbenzyl-N-methyl-1-naphthalenemethylamine hydrochloride. The compound has the molecular formula CHN•HCl, a molecular weight of 353.93, and the following structural formula:
Butenafine HCl is a white, odorless, crystalline powder. It is freely soluble in methanol, ethanol, and chloroform, and slightly soluble in water. Each gram of Mentax (Butenafine hydrochloride) Cream, 1%, contains 10 mg of butenafine HCl in a white cream base of purified water USP, propylene glycol dicaprylate, glycerin USP, cetyl alcohol NF, glyceryl monostearate SE, white petrolatum USP, stearic acid NF, polyoxyethylene (23) cetyl ether, benzyl alcohol NF, diethanolamine NF, and sodium benzoate NF.
Mentax (Butenafine hydrochloride) Clinical Pharmacology
In one study conducted in healthy subjects for 14 days, 6 grams of Mentax (Butenafine hydrochloride) Cream, 1%, was applied once daily to the dorsal skin (3,000 cm) of 7 subjects, and 20 grams of the cream was applied once daily to the arms, trunk and groin areas (10,000 cm) of another 12 subjects. After 14 days of topical applications, the 6-gram dose group yielded a mean peak plasma butenafine HCl concentration, Cmax of 1.4 ± 0.8 ng/mL, occurring at a mean time to the peak plasma concentration, Tmax, of 15 ± 8 hours, and a mean area under the plasma concentration-time curve, AUC of 23.9 ± 11.3 ng-hr/mL. For the 20-gram dose group, the mean Cmax was 5.0 ± 2.0 ng/mL, occurring at a mean Tmax of 6 ± 6 hours, and the mean AUC was 87.8 ± 45.3 ng-hr/mL. A biphasic decline of plasma butenafine HCl concentrations was observed with the half-lives estimated to be 35 hours and > 150 hours, respectively.
At 72 hours after the last dose application, the mean plasma concentrations decreased to 0.3 ± 0.2 ng/mL for the 6-gram dose group and 1.1 ± 0.9 ng/mL for the 20-gram dose group. Low levels of butenafine HCl remained in the plasma 7 days after the last dose application (mean: 0.1 ± 0.2 ng/mL for the 6-gram dose group, and 0.7 ± 0.5 ng/mL for the 20-gram dose group). The total amount (or % dose) of butenafine HCl absorbed through the skin into the systemic circulation has not been quantitated. It was determined that the primary metabolite in urine was formed through hydroxylation at the terminal -butyl side-chain.
In 11 patients with tinea pedis, butenafine HCl cream, 1%, was applied by the patients to cover the affected and immediately surrounding skin area once daily for 4 weeks, and a single blood sample was collected between 10 and 20 hours following dosing at 1, 2 and 4 weeks after treatment. The plasma butenafine HCl concentration ranged from undetectable to 0.3 ng/mL.
In 24 patients with tinea cruris, butenafine HCl cream, 1%, was applied by the patients to cover the affected and immediately surrounding skin area once daily for 2 weeks (mean average daily dose: 1.3 ± 0.2 g). A single blood sample was collected between 0.5 and 65 hours after the last dose, and the plasma butenafine HCl concentration ranged from undetectable to 2.52 ng/mL (mean ± SD: 0.91 ± 0.15 ng/mL). Four weeks after cessation of treatment, the plasma butenafine HCl concentration ranged from undetectable to 0.28 ng/mL.
Butenafine HCl is a benzylamine derivative with a mode of action similar to that of the allylamine class of antifungal drugs. Butenafine HCl is hypothesized to act by inhibiting the epoxidation of squalene, thus blocking the biosynthesis of ergosterol, an essential component of fungal cell membranes. The benzylamine derivatives, like the allylamines, act at an earlier step in the ergosterol biosynthesis pathway than the azole class of antifungal drugs. Depending on the concentration of the drug and the fungal species tested, butenafine HCl may be fungicidal or fungistatic . However, the clinical significance of these data are unknown.
Butenafine HCl has been shown to be active against most strains of the following microorganisms, both and in clinical infections as described in the section:
Epidermophyton floccosumTrichophyton rubrumMalassezia furfurTrichophyton tonsuransTrichophyton mentagrophytes
Mentax (Butenafine hydrochloride) Indications And Usage
Mentax (Butenafine hydrochloride) (butenafine HCl) Cream, 1% is indicated for the topical treatment of the dermatologic infection, tinea (pityriasis) versicolor due to (formerly P. orbiculare). Butenafine HCl cream was not studied in immunocompromised patients. (See .)
Mentax (Butenafine hydrochloride) Contraindications
Mentax (Butenafine hydrochloride) (butenafine HCl) Cream, 1%, is contraindicated in individuals who have known or suspected sensitivity to Mentax (Butenafine hydrochloride) Cream, 1%, or any of its components.
Mentax (Butenafine hydrochloride) Warnings
Mentax (Butenafine hydrochloride) (butenafine HCl) Cream, 1%, is not for ophthalmic, oral, or intravaginal use.
Mentax (Butenafine hydrochloride) Precautions
Mentax (Butenafine hydrochloride) Cream, 1%, is for external use only. If irritation or sensitivity develops with the use of Mentax (Butenafine hydrochloride) Cream, 1%, treatment should be discontinued and appropriate therapy instituted. Diagnosis of the disease should be confirmed either by culture on an appropriate medium, [except (formerly )] or by direct microscopic examination of infected superficial epidermal tissue in a solution of potassium hydroxide.
Patients who are known to be sensitive to allylamine antifungals should use Mentax (Butenafine hydrochloride) (butenafine HCl) Cream, 1%, with caution since cross-reactivity may occur.
Use Mentax (Butenafine hydrochloride) Cream, 1%, as directed by the physician, and avoid contact with the eyes, nose, mouth, and other mucous membranes.
Long-term studies to evaluate the carcinogenic potential of Mentax (Butenafine hydrochloride) Cream, 1%, have not been conducted. Two assays (bacterial reverse mutation test and chromosome aberration test in Chinese hamster lymphocytes) and one 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.
Mentax (Butenafine hydrochloride) Adverse Reactions
In controlled clinical trials, 9 (approximately 1%) of 815 patients treated with Mentax (Butenafine hydrochloride) Cream, 1%, reported adverse events related to the skin. These included burning/stinging, itching and worsening of the condition. No patient treated with Mentax (Butenafine hydrochloride) 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 Mentax (Butenafine hydrochloride) ® 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 Mentax (Butenafine hydrochloride) Cream, 1%.
Mentax (Butenafine hydrochloride) Overdosage
Overdosage of butenafine HCl in humans has not been reported to date.
Mentax (Butenafine hydrochloride) Dosage And Administration
Patients with tinea (pityriasis) versicolor should apply Mentax (Butenafine hydrochloride) Cream, 1%, once daily for two weeks. Sufficient Mentax (Butenafine hydrochloride) Cream should be applied to cover affected areas and immediately surrounding skin of patients with tinea versicolor. If a patient shows no clinical improvement after the treatment period, the diagnosis and therapy should be reviewed.
Mentax (Butenafine hydrochloride) How Supplied
Mentax (Butenafine hydrochloride) (butenafine HCl) Cream, 1%, is supplied in tubes in the following sizes:
15-gram tube (NDC 0378-6151-46)
30-gram tube (NDC 0378-6151-49)
STORE BETWEEN 5° and 30°C (41° and 86°F).
Mylan Pharmaceuticals Inc.Morgantown, WV 26505
REVISED FEBRUARY 2009029.6
Patent # 5,021,458
Mentax (Butenafine hydrochloride)
For Topical Dermatologic Use Only -Not for Oral, Ophthalmic or Intravaginal Use
Each gram contains 10 mg of butenafinehydrochloride, purified water USP, propyleneglycol dicaprylate, glycerin USP, cetyl alcohol NF,glyceryl monostearate SE, white petrolatum USP,stearic acid NF, polyoxyethylene (23) cetyl ether,benzyl alcohol NF, diethanolamine NF and sodium benzoate NF.
Mylan Pharmaceuticals Inc.Morgantown, WV 26505
Store between 5° and 30°C (41° and 86°F).See end flap for lot number and expiration date.
Patent #: 5,021,458
559.5
