Clinical and economic factors in the treatment of onychomycosis.

Onychomycosis is a fungal infection of fingernails and toenails, most cases of which are caused by dermatophytes. The disease accounts for 15% of all nail disease, and affects approximately 2 to 3% of people of all ages and both sexes. Topical treatment with tioconazole, amorolfine or ciclopirox has limited effectiveness. Oral griseofulvin 500 to 1000mg daily has been the mainstay of treatment, but prolonged therapy is required and success rates are low. Therapy with itraconazole 200mg daily for 3 to 6 months is more effective (70 to 85% success), although so-called 'pulse' therapy has shown similar success with potentially fewer adverse effects. Terbinafine 250mg daily produces clinical and mycological cure in approximately 80% of patients treated for 6 and 12 weeks for fingernail and toenail infections, respectively. The overall costs of treating onychomycosis are substantial, and it has been estimated that direct costs for Medicare patients with the disease were $US43 million in 1 year. In addition, the disease has a negative impact on quality of life, in the domains of mental functioning, health concern, social functioning, and physical appearance. Few pharmacoeconomic analyses have been published, but all have indicated an advantage of oral terbinafine over griseofulvin and other oral agents. To date, no economic studies have been performed on topical agents, pulse therapy or combination treatments.