Kinetics and spectrum of activity of oral antifungals: the therapeutic implications

As a wider variety of organisms are being identified in superficial fungal infections, more accurate methods of identification may be required to determine fungal susceptibility. The sensitivity of available methods, such as the minimal inhibitory concentration test, is reviewed. The sensitivities of causative pathogens and the pharmacokinetics of the oral antifungal agents are described. Griseofulvin has a low affinity and ketoconazole a high affinity for keratin, but both require long-term administration to be effective. The pharmacokinetic profiles of terbinafine and itraconazole allow effective short-term treatment with high rates of clinical and mycologic cure. All four agents are active against dermatophytes. Ketoconazole has a broader spectrum of activity but is limited by a rare incidence of hepatotoxicity. Itraconazole has the broadest spectrum of activity.