Lotrimin

Topical Dermatological Antifungals

For external use only.
Avoid contact with the eyes, nose, mouth, or other mucus membranes.
Cleanse the affected skin with soap and water and dry the affected area(s) thoroughly before application.
Wash hands after applying the medication.
Avoid use of occlusive dressings.
For tinea pedis, change shoes and socks at least once daily. Wear well-fitting, ventilated shoes.

contact dermatitis / Delayed / 0-2.0
erythema / Early / 0-2.0

pruritus / Rapid / 0-2.0
skin irritation / Early / 0-2.0

Lotrimin, Lotrimin Ultra, Mentax, Mentax -TC

OTC, Rx

Topical, benzylamine antifungal
Used for the treatment of tinea corporis, tinea cruris, tinea pedis, and tinea versicolor
Potential for cross reactivity in persons who are known to be sensitive to allylamine antifungals

Apply to the affected skin area(s) and immediately surrounding skin once daily for 2 weeks. If no improvement is seen within 2 weeks, reassess diagnosis.

Apply to the affected skin area(s) and immediately surrounding skin once daily for 2 weeks. If no improvement is seen within 2 weeks, reassess diagnosis.

Apply to the affected skin area(s) between and around the toes once daily for 4 weeks or twice daily for 7 days (morning and night). Effectiveness on the bottom or sides of the foot is unknown.

Apply to the affected skin area(s) between and around the toes once daily for 4 weeks or twice daily for 7 days (morning and night). Effectiveness on the bottom or sides of the foot is unknown.

Specific guidelines for hepatic impairment are not available; it appears that no dosage adjustments are needed.

Specific guidelines for renal impairment are not available; it appears that no dosage adjustments are needed.

There are no drug interactions associated with Butenafine products.

Butenafine/Butenafine Hydrochloride/Lotrimin/Lotrimin Ultra/Mentax/Mentax -TC Topical Cream: 1%

2 applications/day topically.

2 applications/day topically.

2 applications/day topically.

12 years: 2 applications/day topically.
1 to 11 years: Safety and efficacy have not been established.

Safety and efficacy have not been established.

Safety and efficacy have not been established.

Butenafine is a benzylamine derivative antifungal that acts by inhibiting the epoxidation of squalene, thus blocking the biosynthesis of ergosterol, an essential component of fungal cell membranes. Depending on the concentration of the drug and the fungal species tested, butenafine may be fungicidal or fungistatic.

Butenafine is administered topically. Low concentrations of butenafine may persist in the plasma for 4 weeks or more after last application. The primary metabolite found in the urine is formed through hydroxylation at the terminal t-butyl side-chain.
 
Affected cytochrome P450 isoenzymes and drug transporters: none

There is some systemic absorption after topical application of butenafine; however, the total dose (% dose) absorbed through the dermis into the systemic circulation has not been quantified. In 11 subjects with tinea pedis, butenafine 1% cream was applied 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 after dosing at 1, 2, and 4 weeks after treatment. The plasma butenafine concentration ranged from undetectable to 0.3 ng/mL. In 24 subjects with tinea cruris, butenafine 1% cream was applied to cover the affected and immediately surrounding skin area once daily for 2 weeks (mean average daily dose: 1.3 +/- 0.2 g), and a single blood sample was collected between 0.5 and 65 hours after the last dose. The plasma butenafine concentration ranged from undetectable to 2.52 ng/mL. At 4 weeks after treatment discontinuation, the plasma butenafine concentration ranged from undetectable to 0.28 ng/mL. In another study in healthy subjects, 6 g of butenafine 1% cream was applied once daily to the dorsal skin (3,000 cm2) and 20 g was applied once daily to the arms, trunk, and groin areas (10,000 cm2) for 14 days. After 14 days, the 6-g dose group (n = 7) had a mean peak plasma concentration (Cmax) of 1.4 +/- 0.8 ng/mL, a mean time to peak plasma concentration (Tmax) of 15 +/- 8 hours, and a mean systemic exposure (AUC) of 23.9 +/- 11.3 ng x hour/mL. For the 20-g dose group (n = 12), the mean Cmax was 5 +/- 2 ng/mL, mean Tmax was 6 +/- 6 hours, and mean AUC was 87.8 +/- 45.3 ng x hour/mL. A biphasic decline of plasma butenafine concentrations was observed with the half-lives estimated to be 35 hours and more than 150 hours, respectively. Low concentrations (mean 0.1 +/- 0.2 ng/mL for the 6-g dose group and 0.7 +/- 0.5 ng/mL for the 20-g dose group) of butenafine were found in the systemic circulation at 7 days after last application.

Use butenafine with caution during pregnancy. There are no adequate and well-controlled studies that have been conducted with topical butenafine during human pregnancy. In studies performed in rats and rabbits utilizing oral terbinafine at doses that were up to 16-times the maximum recommended human dose for tinea versicolor based on body surface area (BSA) comparisons, no treatment-related external, visceral, skeletal malformations or variations or treatment-related effects on postnatal survival, development of the F1 generation or their subsequent maturation and fertility were observed. Additionally, teratogenicity was not observed in rats after administration of subcutaneous butenafine during organogenesis at doses equivalent to 0.5-times the maximum recommended human dose for tinea versicolor based on BSA comparisons.

It is not known if butenafine is excreted in human milk. Because many drugs are excreted in human milk, use caution when using butenafine during breast-feeding.