Terbinafine: a pharmacological and clinical review

Terbinafine (TRB) is an allylamine antifungal agent that has been available for more than a decade. It is now used for the treatment of dermatophytic infections and onychomycosis. Despite several studies having demonstrated the efficacy of terbinafine against nondermatophytic infections including azole-resistant candidiasis, invasive aspergillosis, disseminated fusariosis and scedosporiosis, the role of TRB in the management of these infections remains greatly underappreciated. A brief review of pharmacodynamic, pharmacokinetic, in vitro and in vivo data and published case reports provides insight into the use of terbinafine as a potential adjunct in combination with azoles, polyenes or echinocandins in the management of severe drug-resistant or refractory mycoses. Despite the lack of intrinsic fungicidal activity against several nondermatophytes, when used in combination, particularly with azoles, TRB has demonstrated good antifungal efficacy that could be exploited in clinical practice. As comprehensive human clinical studies are not feasible with the rare occurence of these mycoses, experiments using animal models are essential to evaluate the in vivo efficacy of drug combinations. In summary, terbinafine has established itself as a drug of choice for dermatophytic infections; it must be considered in combination with other antifungal agents for the management of nondermatophytic refractory or resistant yeast/mold infections as well.