Pulsed versus continuous terbinafine dosing in the treatment of dermatophyte onychomycosis.

BACKGROUND: The accepted regimen for terbinafine, one of the most effective treatments for dermatophyte onychomycosis, is continuous administration of 250 mg/day over 16 weeks. A few small studies, however, have raised the possibility of an alternative regimen: pulsed administration of 500 mg/day for 1 week, every 4 weeks (over 16 weeks), without decreasing treatment efficacy. OBJECTIVE: Our aim was to compare the efficacy and safety of both regimens in a large group of patients. METHODS: Retrospective analysis of 260 patients with culture proven dermatophyte onychomycosis treated in seven outpatient clinics run by two dermatologists using one of the terbinafine protocols on a chronological basis: 105 patients were treated using the continuous regimen during 1998/1999 and 155 patients were treated using the pulsed regimen during 1999/2002. Mycological and clinical cure were assessed 2 and 3 months, respectively, after completion of the last therapeutic course. Side effects were documented for the pulse regimen group only and compared with historical data previously published for the continuous protocol. RESULTS: The mycological, clinical and complete (mycological and clinical) cure rates of the toenails were 72.1%, 53.5% and 47.1% in the pulse regimen versus 82%, 35% and 34% in the continuous regimen, respectively (p=0.091, 0.0002 and 0.047, respectively). The mycological, clinical and complete cure rates of the fingernails were 91.7%, 83.3% and 79.2% respectively in the pulse group versus 100% (all parameters) in the continuous group (no significant difference). In general, both regimens were well tolerated and few side effects were reported. CONCLUSION: The pulsed regimen is at least as effective as continuous dosing and thus, at 50% less cost and more convenience, is preferable to a continuous regimen.