MENTAX
Clinical safety rating: caution
Comprehensive clinical and safety monograph for MENTAX (MENTAX).
Inhibits fungal squalene epoxidase, thereby blocking ergosterol biosynthesis and causing accumulation of squalene, leading to fungal cell death.
| Metabolism | Minimal systemic absorption; metabolized primarily via hepatic pathways (CYP450 enzymes) if absorbed, but extensive first-pass metabolism. |
| Excretion | Primarily fecal (biliary) as unchanged drug and metabolites; renal excretion of metabolites accounts for less than 1% of the dose. |
| Half-life | Terminal elimination half-life is approximately 5-6 hours; clinical significance: supports twice-daily dosing for topical antifungal therapy. |
| Protein binding | Greater than 99% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | Systemic Vd not clinically relevant due to minimal absorption; in animal studies, Vd is approximately 0.5 L/kg. |
| Bioavailability | Topical: negligible systemic absorption (less than 5% of applied dose). |
| Onset of Action | Topical: clinical improvement observed within 1-2 weeks of regular application. |
| Duration of Action | Topical: residual antifungal activity persists for 24-48 hours after application; treatment typically continues for 4-6 weeks. |
Butenafine hydrochloride 1% cream: apply to affected area once daily for 2 weeks for tinea pedis; for tinea corporis and tinea cruris, apply once daily for 1 week.
| Dosage form | CREAM |
| Renal impairment | No dosage adjustment required for renal impairment. Butenafine is minimally absorbed systemically and undergoes negligible renal excretion. |
| Liver impairment | No dosage adjustment required for hepatic impairment. Systemic absorption is minimal; no studies in Child-Pugh classes; expected to be safe. |
| Pediatric use | Children 2 years and older: apply butenafine 1% cream once daily for 2 weeks for tinea pedis; for tinea corporis/cruris, apply once daily for 1 week. Safety and efficacy in children under 2 years not established. |
| Geriatric use | No specific dosage adjustment needed; use standard adult dosing. Apply to affected area once daily as directed. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for MENTAX (MENTAX).
| Breastfeeding | Unknown if excreted in human milk; no M/P ratio available. Use with caution, consider risk to infant. |
| Teratogenic Risk | Teratogenic risk cannot be excluded based on animal studies; no adequate human data. First trimester: use only if benefit outweighs risk. Second and third trimesters: limited data, avoid if possible. |
| Fetal Monitoring | Monitor for signs of hypersensitivity, injection site reactions; no specific fetal monitoring required. |
■ 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, or other mucous membranes","Discontinue if irritation or sensitivity develops","Not for ophthalmic, oral, or intravaginal use"] |
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| Fertility Effects | No known effects on fertility in animal studies; no human data. |