Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
ANCOBON vs BUTENAFINE HYDROCHLORIDE
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Flucytosine is converted intracellularly to 5-fluorouracil, which inhibits fungal RNA and DNA synthesis by incorporating into RNA and inhibiting thymidylate synthase.
Inhibits squalene epoxidase, blocking ergosterol synthesis and disrupting fungal cell membrane integrity.
Treatment of systemic fungal infections (e.g., candidiasis, cryptococcosis) in combination with amphotericin B,Off-label: Serious infections caused by susceptible fungi
Topical treatment of tinea pedis (athlete's foot), tinea cruris (jock itch), and tinea corporis (ringworm) due to Trichophyton rubrum, Trichophyton mentagrophytes, and Epidermophyton floccosum.
50-150 mg/kg/day orally divided every 6 hours; intravenous dosing: 50-150 mg/kg/day divided every 12 hours.
1% cream applied topically once daily for 2 weeks for tinea pedis, 1 week for tinea corporis/cruris.
Terminal elimination half-life 2.5-6 hours (normal renal function). Prolonged to 30-250 hours in renal impairment (Cr Cl < 20 m L/min). Half-life correlates with creatinine clearance.
Terminal elimination half-life is approximately 35–40 hours following topical application; long half-life supports once-daily dosing.
Deaminated to 5-fluorouracil in the body; further metabolized via same pathways as fluorouracil.
Not significantly metabolized; undergoes minimal hepatic metabolism via CYP enzymes (unknown specific isoforms).
Primarily renal excretion of unchanged drug (75-90% within 24 hours). Less than 1% eliminated as 5-fluorouracil metabolite. Biliary/fecal excretion negligible.
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.
2-4% bound to plasma proteins (albumin).
Approximately 60–70% bound to plasma proteins, predominantly albumin.
0.6-0.9 L/kg, indicating distribution into total body water. Penetrates well into cerebrospinal fluid (50-100% of serum levels), aqueous humor, and peritoneal fluid.
Not well characterized due to minimal systemic absorption; estimated volume of distribution is very low, consistent with extensive tissue binding or limited distribution.
Oral: 76-89% (well absorbed).
Topical: Systemic bioavailability is less than 5% following topical administration; oral bioavailability has not been established as drug is not used systemically.
GFR >50 m L/min: no adjustment; GFR 10-50 m L/min: 50-100 mg/kg/day divided every 12-24 hours; GFR <10 m L/min: 50-100 mg/kg/day every 24-48 hours; intermittent hemodialysis: 50-100 mg/kg/day with each dialysis session; peritoneal dialysis: 50-100 mg/kg/day every 48 hours.
No dose adjustment required; negligible systemic absorption.
No specific pediatric dosing based on Child-Pugh; use with caution and monitor liver function, potential reduced clearance. No standard adjustment defined.
No dose adjustment required; negligible systemic absorption.
Weight-based: 50-150 mg/kg/day orally divided every 6 hours, or 50-150 mg/kg/day intravenously divided every 12 hours; neonates: 25-100 mg/kg/day intravenously divided every 12 hours.
≥12 years: same as adult; <12 years: safety and efficacy not established; use only if clearly needed.
Start at lower end of dosing range (50 mg/kg/day), adjust based on renal function; monitor for hematologic toxicity.
No specific adjustment; same as adult dosing; monitor for skin irritation.
None.
None.
Hematologic toxicity (leukopenia, thrombocytopenia); renal impairment requires dose adjustment; hepatotoxicity; monitoring of blood counts and renal function recommended.
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.
Hypersensitivity to flucytosine or any component.
Hypersensitivity to butenafine hydrochloride or any components of the formulation.
May be taken with food to reduce gastrointestinal upset. No specific dietary restrictions. Avoid alcohol.
No clinically significant food interactions reported. Butenafine is applied topically and systemic absorption is minimal, so dietary restrictions are not required.
Flucytosine (ANCOBON) is teratogenic in animal studies, causing cleft palate, skeletal anomalies, and fetal resorption. Human data are limited; use in pregnancy only if clearly needed. Potential fetal risk in all trimesters. Contraindicated in first trimester unless life-threatening maternal infection.
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.
Flucytosine is excreted into human breast milk; milk-to-plasma ratio approximately 1.0. Potential for serious adverse reactions in nursing infants; decision to discontinue nursing or drug depends on importance of drug to mother.
Unknown if excreted in human milk; M/P ratio not established. Use with caution in nursing mothers; consider benefits vs risks.
Pregnancy may alter pharmacokinetics due to increased renal clearance and expanded plasma volume. Dose adjustment may be necessary; maintain serum concentrations within therapeutic range (trough 20-50 mcg/m L). Reduce dose in renal impairment, which may occur in pregnancy. No specific pregnancy dose guidelines; use with caution and monitor levels.
No dose adjustment required based on pharmacokinetic changes in pregnancy; topical application has minimal systemic absorption.
Monitor for hepatotoxicity and bone marrow suppression; adjust dose in renal impairment (Cr Cl <50 m L/min requires dose interval extension). Obtain serum levels (desired peak 50-100 mcg/m L, trough <50 mcg/m L) to avoid toxicity. Use with caution in patients with pre-existing hematologic disorders or hepatic dysfunction. Synergistic with amphotericin B for cryptococcal meningitis; avoid concurrent use with nucleoside analogues (e.g., cytarabine) due to antagonism.
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.
Take exactly as prescribed; do not skip doses or stop without consulting your doctor.,May cause nausea and vomiting; taking with food can help.,Report any signs of liver problems (yellowing skin/eyes, dark urine, severe abdominal pain) or unusual bruising/bleeding immediately.,Avoid alcohol while on this medication.,Use effective contraception during treatment; notify your doctor if you become pregnant.,Regular blood tests are required to monitor blood counts and liver function.
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.
No interactions on record
"Etravirine, a non-nucleoside reverse transcriptase inhibitor (NNRTI), is primarily metabolized by CYP3A4 and CYP2C19. Butenafine, an antifungal agent, is also metabolized by CYP3A4. Concurrent use may inhibit the metabolism of butenafine, leading to increased systemic exposure and potential toxicity, including hepatotoxicity or QT prolongation."
"Ranolazine, an antianginal agent, inhibits CYP3A4 and CYP2D6, reducing the metabolism of Butenafine, an antifungal agent typically metabolized by these enzymes. This results in significantly elevated Butenafine serum concentrations, increasing the risk of systemic adverse effects such as hepatotoxicity and QT prolongation. Co-administration may lead to enhanced antifungal efficacy but also potential toxicity."
"Butenafine, an allylamine antifungal, inhibits squalene epoxidase, a key enzyme in ergosterol biosynthesis, leading to fungal cell death. Bepridil, a calcium channel blocker with class I antiarrhythmic properties, prolongs the QT interval by blocking cardiac potassium channels, increasing the risk of torsades de pointes. When combined, butenafine may further inhibit hERG potassium channels in cardiac myocytes, potentiating QT prolongation and elevating the risk of life-threatening ventricular arrhythmias, particularly in patients with preexisting QT prolongation or electrolyte abnormalities."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about ANCOBON vs BUTENAFINE HYDROCHLORIDE, answered by our medical review team.
ANCOBON is a Antifungal that works by Flucytosine is converted intracellularly to 5-fluorouracil, which inhibits fungal RNA and DNA synthesis by incorporating into RNA and inhibiting thymidylate synthase.. BUTENAFINE HYDROCHLORIDE is a Antifungal that works by Inhibits squalene epoxidase, blocking ergosterol synthesis and disrupting fungal cell membrane integrity.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between ANCOBON and BUTENAFINE HYDROCHLORIDE depend on the specific clinical indication. These are both Antifungal agents and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of ANCOBON is: 50-150 mg/kg/day orally divided every 6 hours; intravenous dosing: 50-150 mg/kg/day divided every 12 hours.. The standard adult dose of BUTENAFINE HYDROCHLORIDE is: 1% cream applied topically once daily for 2 weeks for tinea pedis, 1 week for tinea corporis/cruris.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between ANCOBON and BUTENAFINE HYDROCHLORIDE in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. ANCOBON is classified as Category C. Flucytosine (ANCOBON) is teratogenic in animal studies, causing cleft palate, skeletal anomalies, and fetal resorption. Human data are limited; use in pregnancy only if clearly nee. BUTENAFINE HYDROCHLORIDE is classified as Category C. 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.. Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.