Terbinafine, sold under the brand name Lamisil among others, is an antifungal medication used to treat ringworm, pityriasis versicolor, and fungal nail infections. It is either taken by mouth or applied to the skin as a cream or ointment. The cream and ointment are not effective for nail infections.
Common side effects when taken by mouth include nausea, diarrhea, headache, cough, rash, and elevated liver enzymes. Severe side effects include liver problems and allergic reactions. Use during pregnancy is not typically recommended. The cream and ointment may result in itchiness but are generally well tolerated. Terbinafine is in the allylamines family of medications. It works by decreasing the ability of fungi to make sterols.
Terbinafine was discovered in 1991. It is on the World Health Organization's List of Essential Medicines, the most effective and safe medicines needed in a health system. The wholesale cost in the developing world is about 2.20 USD for a 20 gm tube. In the
Terbinafine is mainly effective on the dermatophyte group of fungi.
As a cream or powder, it is used topically for superficial skin infections such as jock itch (tinea cruris), athlete's foot (tinea pedis), and other types of ringworm (tinea corporis). Terbinafine cream works in about half the time required by other antifungals.
Tablets by mouth are often prescribed for the treatment of onychomycosis, a fungal nail infection, typically by a dermatophyte or Candida species. Fungal nail infections are located deep under the nail in the cuticle to which topically applied treatments are unable to penetrate in sufficient amounts. The tablets may, rarely, cause hepatotoxicity, so patients are warned of this and may be monitored with liver function tests. Alternatives to by mouth administration have been studied.
Terbinafine hydrochloride may induce or exacerbate subacute cutaneous lupus erythematosus. Persons with lupus erythematosus should first discuss possible risks with their doctor before initiation of therapy.