A method for the determination of drug effectiveness in onychomycosis. Trials with ketoconazole and griseofulvin ultramicrosize.

A new method for assessing drug effectiveness in onychomycosis is presented. It is based on the clinical experience when three systemic antifungal drugs (griseofulvin, thiabendazole, and ketoconazole) are used against onychomycosis. These drugs act clinically as a barrier to the invasion of the fungus toward the proximal areas of the nail plate. A monthly quantity of normal nail plate should be produced by a given subject after the administration of an effective dose of the antifungal being tested. This quantity is best measured at monthly intervals, and this in fact reflects the normal monthly nail plate growth for the individual. Although there is a slight variation among individuals, most normal healthy subjects grow 1.5 to 2 mm of nail plate per month from their large toenails and 3 to 4 mm of nail plate per month from their fingernails. Utilizing this quantitative system, ketoconazole and griseofulvin ultramicrosize were compared in the treatment of distal subungual onychomycosis by Trichophyton rubrum. In a double-blind study, sixteen patients were treated. It appears that both griseofulvin and ketoconazole can eradicate the episode of onychomycosis. One-year use of a topical antifungal cream after clinical cure of onychomycosis prevented reinfection in the 12-month follow-up period. The use of ketoconazole in long-term therapy may result in serious side effects and should be considered carefully prior to treatment.