Pulsed versus continuous terbinafine dosing in the treatment of dermatophyte onychomycosis

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.

Our aim was to compare the efficacy and safety of both regimens in a large group of patients.

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.

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.

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.