INTRODUCTION
Onychomycosis is a fungal infection of the nail unit
caused by the dermatophytes Trichophyton rubrum
and Trichophyton mentagrophytes in greater than 90%
of cases,1 and most often affects the toenails.2 This fungal infection
affects between 3% to 18% of adults, with prevalence increasing
with age,1,2 and is marked clinically by the presence of
white/yellow or orange/brown patches or streaks in or beneath
the nail plate, subungual hyperkeratosis and debris, and nail
plate thickening. If untreated, the infection often progresses and
may lead to discomfort and pain; in patients with comorbid conditions
such as diabetes, human immunodeficiency virus (HIV),
vascular disease, or renal disease, there is heightened risk of
secondary complications including skin ulceration and systemic infection.3 Recurrence of onychomycosis is common, and may
be related to environmental, occupational, and genetic factors,
or certain clinical features of the initial infection.4-6
Current treatment options for distal subungual onychomycosis
include oral agents, topical treatments, a combination of
systemic and topical therapies, and laser procedures. Terbinafine
and itraconazole are oral antifungal agents approved
by the United States Food and Drug Administration (US FDA)
for the treatment of onychomycosis7,8; terbinafine is the most
frequently prescribed oral antifungal for onychomycosis in
the US and Canada. Although fluconazole and posaconazole
are not approved for the treatment of onychomycosis by the
