Background: terbinafine persists in the nail at effective concentrations for several weeks after discontinuation of treatment.
Objective: Our purpose was to verify whether intermittent terbinafine therapy is effective in dermatophytic onychomycosis and to compare the results of intermittent terbinafine with those of intermittent itraconazole and continuous terbinafine treatment.
Methods: An open, randomized study of 63 patients was performed with three treatment regimens: terbinafine, 250 mg daily (21 patients); terbinafine, 500 mg daily for 1 week every month (21 patients); or itraconazole, 400 mg daily for 1 week every month (21 patients). Treatment was continued for 4 months in toenail infections (60 patients) and 2 months in fingernail infections (3 patients).
Results: At the end of the follow-up period (6 months after discontinuation of treatment) 16 of the 17 patients (94.1%) with toenail onychomycosis were mycologically cured in the terbinafine 250 mg group, 16 of 20 (80%) in the terbinafine 500 mg group, and 15 of 20 (75%) in the itraconazole group.
Conclusion: The percentage of patients who were mycologically cured was higher in the continuous terbinafine group than in the intermittent terbinafine and itraconazole groups, but statistical analysis did not reveal any significant difference between these cure rates.