Binafin

Approved Indications:

• Onychomycosis (Tinea Unguium): Treatment of fingernail and toenail infections caused by dermatophytes such as Trichophyton rubrum and Trichophyton mentagrophytes.
• Tinea Corporis, Tinea Cruris, and Tinea Pedis: Dermatophyte infections of the skin and groin areas.
• Tinea Capitis: Scalp dermatophyte infections.
• Other Superficial Dermatophyte Infections: Such as tinea manuum and tinea barbae.

Off-Label Uses (Clinically Accepted):

• Pityriasis Versicolor: Caused by Malassezia species (less common).
• Cutaneous Candidiasis: Limited use in some cases.

Route: Oral tablets or topical formulations (focus here on oral).

Adults:

• Onychomycosis:
• Fingernails: 250 mg once daily for 6 weeks.
• Toenails: 250 mg once daily for 12 weeks.
• Dermatophyte infections (skin): 250 mg once daily for 2 to 4 weeks.

Pediatrics:

• Use in children aged 4 years and older.
• Dose: 62.5 mg to 125 mg once daily depending on age and weight, typically for 4 to 6 weeks.

Elderly:

• No dosage adjustment necessary; monitor liver function.

Renal Impairment:

• No dose adjustment recommended; monitor clinically.

Hepatic Impairment:

• Avoid use in severe hepatic dysfunction; monitor liver enzymes if therapy necessary.

Administration:

• Can be taken with or without food.
• Swallow tablets whole with water.
• Complete the full prescribed course for best results.

Terbinafine selectively inhibits squalene epoxidase, an enzyme critical in fungal ergosterol synthesis. This inhibition causes accumulation of squalene, toxic to fungal cells, and depletes ergosterol, an essential component of fungal cell membranes. The disruption of membrane integrity leads to fungal cell death, providing a fungicidal effect against dermatophytes and some yeasts.

• Absorption: Well absorbed orally; bioavailability approximately 40%.
• Peak Plasma Concentration: Within 1–2 hours post-dose.
• Distribution: Highly lipophilic; concentrates in skin, nails, and adipose tissue.
• Protein Binding: About 99%.
• Metabolism: Extensively hepatic via CYP enzymes (CYP2C9, CYP1A2, CYP3A4, CYP2C8).
• Half-Life: Approximately 36 hours with repeated dosing.
• Excretion: Primarily renal as metabolites; minimal unchanged drug in urine.

• Pregnancy: FDA Category B – Animal studies show no harm; insufficient human data. Use only if benefits justify risks.
• Lactation: Excreted in breast milk in small amounts. Use with caution; breastfeeding not generally recommended during therapy.

• Primary Class: Antifungal agent
• Subclass: Allylamine antifungal

• Known hypersensitivity to terbinafine or excipients.
• Severe hepatic impairment.
• Caution with concurrent drugs that may interact adversely.

• Hepatotoxicity: Rare but serious; monitor liver enzymes during prolonged therapy.
• Severe Skin Reactions: Including rare Stevens-Johnson syndrome. Discontinue if rash occurs.
• Hematologic Effects: Rare cases of neutropenia and agranulocytosis reported.
• Taste Disturbances: Dysgeusia, usually reversible.
• Autoimmune Conditions: Use cautiously.
• Renal Impairment: Monitor renal function if used.
• Drug Interactions: Moderate CYP2D6 inhibition potential.

Common:

• Gastrointestinal: Nausea, diarrhea, abdominal discomfort.
• Dermatologic: Rash, pruritus.
• Neurological: Headache, dizziness.
• Taste disturbances.

Serious but Rare:

• Hepatitis, jaundice.
• Severe cutaneous adverse reactions.
• Blood dyscrasias.
• Allergic reactions including anaphylaxis.

• CYP2D6 substrates: May increase plasma levels of drugs metabolized by CYP2D6 (e.g., some antidepressants).
• Rifampin: May reduce terbinafine levels.
• Cimetidine: May increase terbinafine levels.
• Alcohol: May increase risk of hepatotoxicity.
• No significant CYP3A4 induction or inhibition.

• No recent major changes to indications or warnings.
• Guidelines endorse terbinafine as first-line for onychomycosis and dermatophytoses.
• Emphasis on liver monitoring during extended therapy.

• Store at 20°C to 25°C (68°F to 77°F).
• Protect from moisture and light.
• Keep in original packaging.
• Do not use past expiration date.