Current trends in onychomycosis therapy: a literature review.

Problems with the use of griseofulvin and ketoconazole in the treatment of onychomycosis have led to studies of three new oral antifungal drugs to treat this disease: fluconazole, itraconazole, and terbinafine. These drugs have been superior in relation to a high rate of cure, shorter duration of treatment, minimal adverse effects, and prolonged duration of remission. Although both fluconazole and itraconazole are structurally related to ketoconazole, their triazole ring is more site-specific than the imidazole ring of ketoconazole, which makes these newer drugs less likely to cause liver toxicity. Terbinafine belongs to a new class of compounds called the allylamines, which are fungicidal rather than fungistatic. Terbinafine has become the first line of therapy in Europe and Canada for onychomycosis, and it has recently been approved in the United States in oral form. Itraconazole and fluconazole are available in the United States, but fluconazole is not yet approved for treatment of onychomycosis.