Terbinafine (Lamisil, Zabel) - Because fungus-infested toenails are really gross

• allylamine-containing antifungal/antimycotic/killer-of-fungi
• does its thing by inhibiting squalene epoxidase, a fungal enzyme that is required for the synthesis of ergosterol, a necessary component of fungal cell membranes
• in addition, inhibition of this enzyme results in its substrate, squalene, accumulating to toxic levels within fungal cells, providing a second avenue of destruction
• administered topically (e.g. as a cream or ointment) to kill dermatophytes (parasitic fungi that infect the skin), including those responsible for jock itch, athlete's foot, and ringworm
• administered orally to treat fungal nail infections, since they are usually deep beneath the nail in the cuticle and so protected from topical preparations
• is highly soluble in fat/lipid, which means that it is rapidly absorbed and widely distributed throughout the body following administration
  
• accumulates in the cuticles and kills the fungus
• has been linked to liver toxicity, including things like cholestatic hepatitis, possibly mediated by a metabolite of the drug
• thus it is important to monitor liver function during therapy with the drug
  

- Ajit C, Suvannasankha A, Zaeri N, Munoz SJ. Terbinafine-associated hepatotoxicity. Am J Med Sci. 2003 May;325(5):292-5.
- Darkes MJ, Scott LJ, Goa KL. Terbinafine: a review of its use in onychomycosis in adults. Am J Clin Dermatol. 2003;4(1):39-65.
- http://en.wikipedia.org/wiki/Terbinafine