LOTRIMIN ULTRA
Clinical safety rating: caution
Comprehensive clinical and safety monograph for LOTRIMIN ULTRA (LOTRIMIN ULTRA).
Butenafine hydrochloride is a synthetic antifungal agent that inhibits the enzyme squalene epoxidase, thereby blocking the biosynthesis of ergosterol, an essential component of fungal cell membranes, leading to fungal cell death.
| Metabolism | Hepatic metabolism via cytochrome P450 enzymes (specific isoforms not well characterized); undergoes oxidative metabolism. |
| Excretion | Primarily fecal (approx. 80%) as unchanged drug and metabolites; renal excretion accounts for <10% of the dose. |
| Half-life | Terminal elimination half-life is approximately 24-48 hours (range 20-50 hours), supporting once-daily topical application. |
| Protein binding | Approximately 90-99% bound to serum proteins, primarily albumin. |
| Volume of Distribution | Volume of distribution (Vd) is approximately 1-2 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Topical: Systemic absorption is minimal (approximately 0.5-2%) following topical application to intact skin. |
| Onset of Action | Topical: Relief of symptoms (itching, burning) may begin within 1-2 days; clinical improvement of fungal lesions typically seen within the first week of treatment. |
| Duration of Action | Topical: Therapeutic effect lasts for the duration of treatment and beyond (fungistatic); continued application for 1-2 weeks after symptom resolution is recommended to prevent recurrence. |
Adults: Apply butenafine hydrochloride 1% cream topically once daily for 7 days for tinea pedis; for tinea cruris and tinea corporis, apply once daily for 14 days.
| Dosage form | CREAM |
| Renal impairment | No dose adjustment required for topical application; negligible systemic absorption. |
| Liver impairment | No dose adjustment required for topical application; negligible systemic absorption. |
| Pediatric use | Children ≥12 years: Same as adult dosing. Children <12 years: Safety and efficacy not established. |
| Geriatric use | No specific dose adjustment; use same as adult dosing. Consider skin integrity and potential for increased percutaneous absorption. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
Comprehensive clinical and safety monograph for LOTRIMIN ULTRA (LOTRIMIN ULTRA).
| Breastfeeding | It is unknown whether butoconazole is excreted in human breast milk after topical application. However, due to minimal systemic absorption, it is unlikely to pose a risk to the nursing infant. Caution is advised; M/P ratio not available. |
| Teratogenic Risk | Butoconazole nitrate, the active ingredient in LOTRIMIN ULTRA, has not been associated with an increased risk of major congenital malformations when used topically during pregnancy. However, due to limited data, first trimester use is cautionary. Second and third trimester use is generally considered safe; systemic absorption is minimal (<5%). FDA pregnancy category C. |
■ FDA Black Box Warning
None.
| Serious Effects |
["Hypersensitivity to butenafine hydrochloride or any component of the formulation."]
| Precautions | ["For external use only; avoid contact with eyes, mouth, or mucous membranes.","Not recommended for use in children under 12 years of age.","Discontinue if irritation or sensitization occurs.","Prolonged use may lead to overgrowth of nonsusceptible organisms."] |
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| Fetal Monitoring | No specific monitoring is required beyond routine obstetric care. In cases of prolonged use or application over large areas, monitor for signs of systemic absorption or local irritation. |
| Fertility Effects | No adverse effects on fertility have been reported in animal studies or human data. Topical application results in negligible systemic exposure, unlikely to impact fertility. |