BUTENAFINE HYDROCHLORIDE
Clinical safety rating: caution
Comprehensive clinical and safety monograph for BUTENAFINE HYDROCHLORIDE (BUTENAFINE HYDROCHLORIDE).
Inhibits squalene epoxidase, blocking ergosterol synthesis and disrupting fungal cell membrane integrity.
| Metabolism | Not significantly metabolized; undergoes minimal hepatic metabolism via CYP enzymes (unknown specific isoforms). |
| Excretion | Primarily metabolized in the liver; minimal excretion of unchanged drug. Less than 5% of a topical dose is absorbed systemically; excreted in urine and feces as metabolites. |
| Half-life | Terminal elimination half-life is approximately 35–40 hours following topical application; long half-life supports once-daily dosing. |
| Protein binding | Approximately 60–70% bound to plasma proteins, predominantly albumin. |
| Volume of Distribution | Not well characterized due to minimal systemic absorption; estimated volume of distribution is very low, consistent with extensive tissue binding or limited distribution. |
| Bioavailability | Topical: Systemic bioavailability is less than 5% following topical administration; oral bioavailability has not been established as drug is not used systemically. |
| Onset of Action | Topical: Clinical improvement noted within 1–2 weeks of consistent application. |
| Duration of Action | Topical: Therapeutic effect persists for at least 24 hours after single application; treatment typically continues for 2–4 weeks for tinea infections. |
1% cream applied topically once daily for 2 weeks for tinea pedis, 1 week for tinea corporis/cruris.
| Dosage form | CREAM |
| Renal impairment | No dose adjustment required; negligible systemic absorption. |
| Liver impairment | No dose adjustment required; negligible systemic absorption. |
| Pediatric use | ≥12 years: same as adult; <12 years: safety and efficacy not established; use only if clearly needed. |
| Geriatric use | No specific adjustment; same as adult dosing; monitor for skin irritation. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for BUTENAFINE HYDROCHLORIDE (BUTENAFINE HYDROCHLORIDE).
| Breastfeeding | Unknown if excreted in human milk; M/P ratio not established. Use with caution in nursing mothers; consider benefits vs risks. |
| Teratogenic Risk | FDA Pregnancy Category B. No evidence of teratogenicity in animal studies; inadequate human data. Risk cannot be ruled out; avoid use in first trimester unless clearly needed. |
| Fetal Monitoring |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to butenafine hydrochloride or any components of the formulation."]
| Precautions | ["For external use only.","Avoid contact with eyes, nose, mouth, and other mucous membranes.","Discontinue if irritation or sensitization occurs.","Not recommended for treatment of onychomycosis or scalp infections."] |
| Food/Dietary | No clinically significant food interactions reported. Butenafine is applied topically and systemic absorption is minimal, so dietary restrictions are not required. |
| Clinical Pearls |
Loading safety data…
| No specific monitoring required. Use as directed; monitor for local irritation or hypersensitivity reactions. |
| Fertility Effects | No known adverse effects on fertility in animal studies; no human data available. |
| Butenafine hydrochloride is a benzylamine antifungal with fungicidal activity against dermatophytes (e.g., Trichophyton rubrum, T. mentagrophytes, Epidermophyton floccosum) and yeasts (Malassezia spp.). It inhibits squalene epoxidase, leading to accumulation of squalene and disruption of fungal cell membrane synthesis. Applied once or twice daily for 1–4 weeks depending on indication. For tinea pedis (athlete's foot), treatment should extend 1 week beyond resolution to prevent recurrence. Avoid occlusion unless directed; may increase irritation. Contraindicated in hypersensitivity to any component. For severe or resistant cases, consider combination with keratolytics (e.g., salicylic acid) to enhance penetration. |
| Patient Advice | Apply butenafine cream exactly as prescribed: clean and dry the affected area before application. · Use enough medication to cover the affected skin and a small margin of healthy surrounding skin. · Wash your hands after applying, unless treating the hands. · Do not cover the treated area with bandages or dressings unless instructed by your doctor. · Complete the full course of treatment even if symptoms improve, to prevent recurrence. · Notify your doctor if no improvement after 2–4 weeks or if irritation, redness, or blistering occurs. · Avoid contact with eyes, mouth, nose, or broken skin; if accidental contact occurs, rinse with water. · Do not use for conditions other than those prescribed; butenafine is for external use only. |