terbinafina

Terbinafina, known in English as terbinafine and in some languages as terbinafina, is an antifungal medication used to treat various dermatophyte infections of the skin and nails. It is available in oral and topical formulations, including tablets, creams, gels, and nail lacquer. Terbinafine is commonly prescribed for conditions such as tinea pedis (athlete’s foot), tinea cruris (jock itch), tinea corporis (body ringworm), and onychomycosis caused by dermatophytes.

Mechanism of action: Terbinafine inhibits the fungal enzyme squalene epoxidase, a key step in ergosterol synthesis. This leads to the accumulation of squalene and disruption of the fungal cell membrane, producing a fungicidal effect against many dermatophytes. The drug tends to concentrate in skin and nails, which supports its effectiveness in nail infections but also explains potential for longer treatment courses.

Indications and spectrum: Terbinafine is most effective against dermatophyte fungi that cause skin and nail infections. It is generally less active against yeasts such as Candida. Topical preparations are used for mild to moderate skin infections or for prevention of recurrence after systemic therapy in some cases, while oral therapy is preferred for confirmed or extensive onychomycosis or scalp infections when topical treatment is unlikely to succeed.

Administration and duration: Oral terbinafine is typically given as 250 mg daily, with treatment durations varying by site and severity; nail infections often require several months of therapy. Topical forms are applied to the affected area daily for a period defined by the infection type and response.

Safety and interactions: Terbinafine can cause gastrointestinal upset, headaches, rash, and taste disturbance. Rare but serious hepatotoxicity has been reported; baseline and, if needed, periodic liver function tests are recommended, especially with prolonged use. The drug inhibits CYP2D6 and can interact with medications metabolized by this enzyme. It should be used with caution in liver disease and during pregnancy or breastfeeding, as advised by a clinician.