Terbinafine, a synthetic antifungal of
allylamine class, has fungicidal activity against dermatophytes, moulds and certain dimorphic fungi and fungistatic activity against Candida albicans. Following
oral administration the
terbinafine is absorbed rapidly (>70%) and reaches within 2 hours the peak plasma concentration. The
drug is highly lipophilic and keratophilic and is highly bound to
plasma protein (>90%) with a bioavailability of 70% to 80%. The
drug is rapidly delivered and it is present in the stratum corneum, sebum, nails and hair for months after stopping the medication. The
drug has been proven to be the choice treatment in the
therapy of
onychomycosis as it is very effective, well tolerated and has a relatively low potential for drug interactions. The pharmacologic and pharmacokinetic properties of
terbinafine give strong support to the possibility that the pulse
therapy may be equally effective in
onychomycoses, possibly reducing medication costs and
drug exposure. Several therapeutic patterns have been proposed: weekly intermittent
terbinafine (500 mg/d for 1 week each month for 4 months), or single-dose
terbinafine (1000 mg per month for 4 months). Use of topical
terbinafine 1% may be practical where the
tinea involvement is not extensive or chronic. Recently, the
terbinafine is available in a novel topical
solution (film-forming
solution--FFS) effective in the treatment of
tinea pedis (
athlete's foot).