Mentax (butenafine HCl cream) 1% - 4 indications

• interdigital tinea pedis (athletes foot); approved October 1996
• tinea corporis (ringworm) and tinea cruris (groin fungus); approved January 1997
• tinea (pityriasis) versicolor due to Malassezia furfur (formerly Pityrosporum orbiculare); approved June of 2001

General Information

Mentax 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.

Mentax is specifically indicated for the topical treatment of the following dermatologic infections:

• tinea (pityriasis) versicolor due to M. furfur (formerly P. orbiculare)
• interdigital tinea pedis (athlete’s foot)
• tinea corporis (ringworm) and tinea cruris (jock itch) due to E. floccosum, T. mentagrophytes, T. rubrum, and T. tonsurans

Mentax is supplied as a cream for topical administration. Sufficient Mentax Cream should be applied to cover affected areas and immediately surrounding skin. If a patient shows no clinical improvement after the treatment period, the diagnosis and therapy should be reviewed. The recommended dosing and administration is as follows:

• Patients with tinea (pityriasis) versicolor should apply Mentax once daily for two weeks.
• Patients with interdigital tinea pedis should apply Mentax twice daily for 7 days OR once daily for 4 weeks 
• Patients with tinea corporis or tinea cruris should apply Mentax once daily for two weeks

Mechanism of Action

Mentax contains the synthetic antifungal agent, butenafine hydrochloride. 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 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 in vitro. However, the clinical significance of these in vitro data is unknown.

Side Effects

Adverse effects associated with the use of Mentax may include, but are not limited to, the following:

• burning/stinging
• itching
• worsening of the condition
•  contact dermatitis
• erythema
• irritation
• itching

Indication 1 - interdigital tinea pedis (athletes foot)

approved October 1996

Clinical Trial Results

Once Daily Four Week Dosing:

Data are from two controlled studies in which Mentax Cream, 1%, was used once daily for 4 weeks. Efficacy was assessed on the following parameters: “Mycological Cure” defined as both negative KOH and culture. “Effective Treatment” refers to patients who had a “Mycological Cure” and an Investigator’s Global of either “Excellent” (80% to 99% improvement) or “Cleared” (100% improvement). “Overall Cure” refers to patients who had both a “Mycological Cure” and an Investigator’s Global Assessment of “Cleared”(100% improvement). Rates are Mentax versus placebo, respectively. Mycological Cure: 89% (83/93) versus 57% (51/90). Effective Treatment: 57% (53/93) versus 28% (25/90). Overall Cure: 15% (14/93) versus 8% ( 7/90). 

Twice-Daily One Week Dosing

Data are from two controlled studies in which Mentax Cream, 1%, was used twice daily for 1 week. Patients were treated for 1 week and evaluated 5 weeks post-treatment. Efficacy was assessed using the same parameters as above. Rates are Mentax versus placebo. Mycological Cure: 79% versus 20%. Effective Treatment: 38% versus 7%. Overall Cure: 15% versus 0.7%.

Indications 2 and 3 - tinea corporis (ringworm) and tinea cruris (groin fungus)

approved January 1997

Clinical Trial Results

Two separate studies compared Mentax Cream to vehicle applied once daily for 2 weeks in the treatment of tinea corporis and tinea cruris. Patients were treated for 2 weeks and evaluated 4 weeks post-treatment. Efficacy was assessed on the following parameters: “Mycological Cure” defined as both negative KOH and culture. “Effective Treatment” refers to patients who had a “Mycological Cure” and an Investigator’s Global of either “Excellent” (80% to 99% improvement) or “Cleared” (100% improvement). “Overall Cure” refers to patients who had both a “Mycological Cure” and an Investigator’s Global Assessment of “Cleared”(100% improvement). Statistical significance (Mentax vs. vehicle) was achieved for all patient outcome categories at Week 2 (end of treatment) and Week 6 (4 weeks post-treatment). Results are Mentax versus vehicle, respectively.

• Tinea Corporis:
  • Mycological Cure: Week 2: 88% versus 28%; Week 6: 88% versus 17%
  • Effective Treatment: Week 2: 60% versus 17%; Week 6: 81% versus 14%
  • Overall Cure: Week 2: 31% versus 3%; Week 6: 67% versus 14%

• Tinea Cruris
  • Mycological Cure: Week 2: 78% versus 11%; Week 6: 81% versus 13%
  • Effective Treatment: Week 2: 57% versus 8%; Week 6: 73% versus 5%
  • Overall Cure: Week 2: 32% versus 8%; Week 6: 62% versus 3%

Indication 4 - tinea (pityriasis) versicolor

approved June of 2001

Clinical Trial Results

Two separate studies (Study 31 and Study 32) compared Mentax Cream to vehicle applied once daily for 2 weeks in the treatment of tinea (pityriasis) versicolor. Patients were treated for 2 weeks and were evaluated at the following weeks post-treatment: 2 (Week 4) and 6 (Week 8). Efficacy was based on the following measurements: “Negative Mycology”, defined as absence of hyphae in a KOH preparation of skin scrapings, i.e.; no fungal forms seen or the presence of yeast cells (blastospores) only. “Effective Treatment”, defined as Negative Mycology plus total signs and symptoms score (on a scale from zero to three) for erythema, scaling, and pruritus equal to or less than 1 at Week 8. “Complete Cure” refers to patients who had negative mycology plus sign/symptoms scores of zero for erythema, scaling, and pruritus. Statistical significance (Mentax vs. vehicle) was achieved for Effective Treatment, but not Complete Cure at 6 weeks post-treatment in Study 31. Marginal statistical significance (Mentax vs. vehicle) was achieved for Effective Treatment but not Complete Cure at 6 weeks post-treatment in Study 32.